How to Switch Your Accounting Software Without Losing Data: The Complete Guide for German Businesses

Switching accounting software is one of the most critical decisions a German business can make—yet it's also one of the most feared. The anxiety is understandable. You're sitting on years of financial data, complex tax obligations under GoBD regulations, and a working relationship with your Steuerberater (tax advisor). The thought of migrating everything feels overwhelming, risky, and potentially disastrous if something goes wrong.

But here's the truth: businesses switch accounting software every single day without losing data or violating compliance requirements. The difference between a smooth transition and a nightmare scenario? Planning, preparation, and knowing exactly what steps to follow.

This guide walks you through the entire process—from recognizing when it's time to switch, through data migration, tax advisor coordination, and GoBD compliance verification. Whether you're moving from Lexware to lexoffice, upgrading from Excel-based bookkeeping, or consolidating multiple systems, this is your complete roadmap.

By the end of this article, you'll understand exactly what needs to happen, when it needs to happen, and how to protect your business during the transition. Let's begin.

Why Switching Your Accounting Software Matters Now

Many business owners stay with outdated accounting software far longer than necessary. The reasons are always the same: 'It's working fine,' 'I don't want to mess with it,' or 'The migration seems too complicated.' But the hidden costs of staying with inadequate software are staggering.

Outdated systems drain resources through manual data entry, inability to automate invoice processing, weak bank connectivity, and limited integration with other business tools. If your software doesn't support modern SEPA payments, automated reconciliation, or cloud-based collaboration, you're paying in lost productivity every single day.

Worse, if your current software doesn't meet current GoBD requirements or lacks proper audit trails, you're running compliance risk. German tax authorities take digital bookkeeping rules seriously, and penalties for non-compliance can reach thousands of euros.

The good news? Modern accounting software in 2026 is mature, stable, and specifically designed to handle German compliance requirements. And the migration process, when done correctly, is far simpler than you think.

When Is the Right Time to Switch?

Timing matters enormously in an accounting software migration. Switching mid-fiscal year creates unnecessary complexity—you'd be reconciling across two systems for the same period, tracking open items across platforms, and creating audit confusion. Understanding when to switch protects your business from unnecessary complications.

7 Clear Signs You Should Switch Now

• Your current software doesn't support SEPA/IBAN payment standards or modern banking integrations
• You're manually entering data from bank statements instead of automated reconciliation
• Your tax advisor says your current system doesn't meet their requirements for DATEV export or audit compliance
• You're using multiple unintegrated spreadsheets alongside your accounting software
• The software lacks API connections to your CRM, e-shop, or other critical business tools
• Your team spends hours each week on manual bookkeeping tasks that should be automated
• The vendor no longer provides updates or support, or is increasing prices aggressively

The Ideal Migration Timeline: January 1

The absolute best time to switch accounting software in Germany is January 1—the first day of a new fiscal year. This minimizes complexity because you're starting fresh with opening balances rather than trying to mid-stream reconcile across two systems. Most German businesses operate on a January 1 to December 31 fiscal year (Geschäftsjahr), which makes this the natural transition point.

If you missed January 1, the next best options are either waiting until the next fiscal year, or—if absolutely necessary—migrating at the end of a calendar month. Never switch in the middle of a month unless you have no other choice.

The Pre-Migration Audit: Know What Data You Have

Before you even evaluate new software, you need a complete inventory of your current data. This isn't a casual review—it's a forensic audit. You're answering the question: 'What am I actually bringing into the new system, and what format is it in?'

Five Categories of Data You Need to Audit

• Master data: Chart of accounts (Kontenrahmen), customer records (Debitor), supplier records (Kreditor), cost centers, tax codes
• Historical bookings: Every journal entry, invoice, and receipt from the past 10 years (required under GoBD)
• Open items: Outstanding customer invoices (offene Posten), outstanding supplier invoices, credit notes pending processing
• Fixed assets: The asset register (Anlagenspiegel), depreciation schedules (Abschreibungsplan), and acquisition history
• Bank and payment data: Bank account information, processed payments, bank reconciliation data, payment methods

Understanding Your Export Format Options

Most accounting software can export data in multiple formats. Understanding which format you have—and which one your new software requires—is critical. Here are the main formats you'll encounter:

• DATEV standard format: The most common exchange format for German accounting software. This is your safest export format
• CSV (comma-separated values): Universal format but loses formatting and requires careful mapping when importing
• XML/XLS: Some software exports in proprietary XML or Excel formats that may not be directly importable elsewhere
• API data exports: Newer cloud software allows automated API exports that can be directly imported by other systems
• PDF/image archives: Critical if you have archived receipts (Belege), but this is document storage, not accounting data

GoBD Compliance Obligations During Migration

German tax law (GoBD—Grundsätze zur Ordnungsmäßigkeit der Buchführung und Abrechnung Digital) mandates strict requirements for digital accounting, including during system migrations. Understanding these requirements now prevents compliance disasters later.

First: You must retain all original accounting data for 10 years after the end of the fiscal year. This means when you switch systems, your old system's data must be properly archived and accessible for audit purposes. You can't just delete it.

Second: GoBD requires that all accounting data maintain its integrity and remain immutable after creation. During migration, you must ensure that no data is altered, deleted, or corrupted in transit. This is why proper migration tools and procedures matter—a sloppy spreadsheet copy-paste risks creating non-GoBD-compliant records.

Third: You must create and maintain Verfahrensdokumentation (process documentation) for every system you use. This means documenting how your new accounting software works, what master data it contains, and how it exports data for audit purposes. Your tax advisor will need this.

Pre-Migration Documentation Checklist

• Complete export of current system's master data with all fields and account codes
• List of all open items (unpaid invoices to customers and suppliers) with amounts, due dates, and aging
• Fixed asset register showing all equipment, costs, depreciation method, and useful life
• Chart of accounts (Kontenrahmen) used—note whether you're using SKR03 (for services), SKR04 (for retail/manufacturing), or a custom structure
• Reconciliation statement from your last tax return or accountant report showing all account balances
• List of all active payment methods: SEPA direct debit, SEPA credit transfer, PayPal, credit cards, etc.
• Screenshot or export of your current system's setup: payment terms, tax rates, recurring invoices, dunning procedures
• Password reset: Ensure you have administrative access to your current system and can export data unobstructed

Choosing Your New Accounting Software: The Complete Comparison

Germany's accounting software market has consolidated significantly in recent years. Where you once had dozens of incompatible options, today the decision typically comes down to five major platforms, each with different strengths. The right choice depends on your specific needs, not on general popularity.

Feature Comparison: lexoffice vs sevDesk vs DATEV vs Sage vs Billomat

This table reflects 2026 pricing and features. Let's break down what each platform does best:

lexoffice: The Data Import Champion

lexoffice (owned by Lexware) has invested heavily in migration tools and import features. If you're switching from another platform, lexoffice makes it easy. They offer both automated CSV import and manual mapping tools, with specific import profiles for common source systems like Lexware, Fastbill, and even Excel. They also provide a direct DATEV export that tax advisors prefer. Cloud-based, trusted by over 1 million German businesses, and strong API integration with e-commerce platforms. Cost: €300-900 annually depending on features.

sevDesk: The All-in-One Ecosystem

sevDesk combines invoicing, accounting, time tracking, and inventory in one platform. If you need more than just accounting—for example, you're also managing projects or equipment inventory—sevDesk's integration might justify the switch. Data import is solid though not quite as smooth as lexoffice. DATEV export is available but you'll be exporting rather than having direct tax advisor integration. Cost: €360-960 annually.

DATEV Unternehmen Online: The Tax Advisor's Native Platform

If your tax advisor strongly recommends it, DATEV is the safest choice. It's the professional standard used by most German accountants and tax advisory firms. The downside: DATEV is significantly more expensive (€500-2000+), requires more training, and is overkill for small to mid-sized businesses doing their own bookkeeping. DATEV is usually the choice for larger GmbHs or when your tax advisor prefers direct integration. Cloud and on-premise options both available.

Sage 50: Legacy Desktop Option

Sage 50 is a mature desktop accounting solution still used by some businesses. It's not cloud-native, which means your data sits on your computer, collaboration is limited, and mobile access is non-existent. Unless you have existing Sage infrastructure, this is not recommended for a migration—you'd be moving backward in functionality. Included only for completeness.

Billomat: The SME-Focused Platform

Billomat is purpose-built for freelancers and small businesses. Clean interface, strong invoicing features, solid accounting backbone, good integration library. The trade-off: fewer advanced features for larger businesses and a smaller ecosystem of integrations compared to lexoffice. Price is attractive at €240-600 annually. Good choice if you're a solopreneur or micro-business.

Cloud vs. Desktop: Why Cloud Is Now Non-Negotiable

If you're considering switching to desktop accounting software (like Sage 50 or Lexware Desktop), stop. The era of desktop accounting is over. Here's why:

• Cloud systems automatically backup your data (eliminating catastrophic loss risk from hard drive failure)
• Cloud systems update automatically with security patches and new GoBD-compliant features
• Cloud systems allow your tax advisor, accountant, and team members to securely access your data without sharing passwords
• Cloud systems provide real-time bank reconciliation and payment processing
• Cloud systems integrate with modern SEPA payment systems, e-commerce platforms, and business tools
• Cloud systems provide better audit trails for GoBD compliance

DATEV Compatibility: The Deal-Breaker Question

Here's a critical question your tax advisor will ask: 'Does your new software export to DATEV format?' This single compatibility factor eliminates half the software options out there and should heavily influence your choice.

Why? Because 70% of German tax advisors use DATEV as their primary platform. When you send your monthly or annual bookkeeping data to your tax advisor, they expect it in DATEV format. Software that exports clean DATEV data saves your advisor significant manual work, reduces errors, and costs less in advisory fees.

Software with poor or no DATEV export forces your tax advisor to re-enter your data manually—and they'll likely charge you for that extra work. This hidden cost can easily exceed software license savings.

Action item: Before choosing new software, email your tax advisor: 'I'm considering [software name]. Do you accept DATEV format exports from this platform, or would I need to export differently?' Their answer heavily influences which platform to choose.

Tax Advisor Access Models

• Direct integration (DATEV, lexoffice): Tax advisor has direct read-only access to your accounting data in the software itself
• API export (sevDesk, Billomat): You manually or automatically export data; advisor imports it into their system
• DATEV export with CSV fallback: Software exports in DATEV format; advisor imports into DATEV Unternehmen Online
• No integration: You must manually export reports and send to advisor (this is outdated and creates errors)

Data Migration Step by Step: The Technical Process

Now we move into the technical details. This section walks through exactly what happens when you migrate data from your old system to your new system. Don't skip this—understanding the process builds confidence and helps you catch problems early.

Step 1: Export and Map Master Data

Master data is the static information your accounting system relies on: your chart of accounts, customer records, supplier records, and other foundational data. This data comes first.

• Export your chart of accounts (Kontenrahmen) from your old system, noting which standard you're using (SKR03 for service businesses, SKR04 for retail/manufacturing)
• Export all customer records with: Customer number, name, address, email, payment terms, tax ID, and any custom fields
• Export all supplier records with the same information
• If you use cost centers or profit centers, export those too
• Review each export in Excel to ensure all fields have values and no data is corrupted

The 'mapping' step is crucial. Most accounting software uses different field names and structures. A customer's 'phone number' in your old system might be stored differently in your new system. You need to ensure that when you import this data, fields align correctly. Most modern software has import wizards that handle this—you'll see a visual mapping where you select 'Source field → Target field.'

Step 2: Migrate Open Items (Offene Posten)

Open items are critical: these are unpaid customer invoices (outstanding receivables) and unpaid supplier invoices (outstanding payables). Losing track of open items creates immediate cash flow chaos and lost credibility with suppliers.

For each open item, you need: Invoice number, customer/supplier, amount, due date, and payment date (if partially paid). Most accounting software can export a complete 'open items' report. Import this as transaction data—not as manual journal entries.

Critical: When you import open items, set their transaction date to the date they originally appeared in your old system, not the migration date. This preserves proper aging for your reports.

Step 3: Create Opening Balances (Saldenvortrag)

On January 1 (your migration date), every account in your chart of accounts has a balance. This balance becomes your opening balance in the new system. This is called Saldenvortrag in German accounting.

Get this from your accountant or tax advisor: a balance sheet (Bilanz) as of December 31 of the previous year showing all account balances. You'll create a single journal entry on January 1 in your new system that establishes these opening balances. Most accounting software has an automated feature for this.

This single entry ensures that your January 1 account balances match your previous system's December 31 balances. It's the foundation of everything that follows.

Step 4: Migrate the Fixed Asset Register (Anlagenbuchhaltung)

If your business owns equipment, computers, vehicles, or other fixed assets, you have an asset register (Anlagenspiegel). This contains: asset description, acquisition date, acquisition cost, depreciation method (straight-line, declining balance), useful life (5 years for computers, 8 years for vehicles, etc.), and accumulated depreciation.

Losing this data doesn't just create accounting confusion—it violates tax law because you won't have proper depreciation schedules for your tax return. Export your complete asset register from your old system (usually in the Fixed Assets module), then import it into your new system's Fixed Assets module using the same mapping process as master data.

Verify that depreciation calculations carry forward correctly. If an asset was acquired on March 15, 2021, and depreciated for four years in your old system, the accumulated depreciation should transfer, and your new system should only calculate depreciation going forward (not recalculate from acquisition).

Step 5: Configure Recurring Bookings

Recurring bookings are transactions that happen regularly: monthly rent payments, insurance premiums, utility bills, loan payments, etc. These aren't typical invoices; they're standing transactions that appear every month.

Export a list of these from your old system, then manually set up each one in your new system's 'recurring transaction' or 'standing orders' feature. This only takes an hour or two and prevents you from manually re-entering them every month.

Step 6: Set Up Bank Connections

Modern accounting software connects directly to your bank for automatic transaction importing and reconciliation. This is one of the biggest time-savers in modern accounting but requires setup.

You'll use FinTS (German banking standard) or HBCI connection details to link your business bank account. You typically need your online banking credentials and PIN/password. Once connected, new transactions download automatically every day, ready for you to categorize and reconcile.

Setup usually takes 15 minutes. Your new software will guide you through the process. Make sure your bank account is properly configured before going live on January 2.

Real-World Example: Migrating from Lexware to lexoffice

Here's how this migration typically plays out in practice. Maria runs a 15-person marketing consulting business using Lexware Buchhalter (desktop software). She's decided to switch to lexoffice for better cloud collaboration, automatic bank imports, and tax advisor integration.

Her timeline:

• October 15: She audits her data in Lexware, exports the complete chart of accounts, customer list, and supplier list as CSV files. She also prepares her asset register
• October 22: She calls her tax advisor Steffen and says, 'I'm switching to lexoffice on January 1. Will that work for you?' Steffen confirms he accepts lexoffice DATEV exports
• November 5: Maria sets up lexoffice, completes the onboarding, and begins testing with sample data. She's not yet importing real data
• November 20: She imports her master data (chart of accounts, customers, suppliers) into lexoffice and verifies everything looks correct
• December 10: She imports all open items (unpaid invoices) and creates the opening balance entry with Steffen's help
• December 22: She sets up her bank account connection and tests it with a small transaction
• December 31: Final verification: she confirms her January 1 opening balances match her December 31 Lexware balances
• January 2: She enters the first transaction in lexoffice. She marks 'Lexware archived' and moves the old system to backup storage
• February 2: After one month of successful operation in lexoffice, she formally archives her Lexware data according to GoBD requirements

Total process time: 3.5 months. Actual data import time: approximately 8 hours. This is realistic for a small business with moderate data volume.

Involving Your Tax Advisor: The Critical Partnership

Your tax advisor (Steuerberater or accountant) is not optional in this process—they're your most important partner. Early involvement prevents disasters and ensures your new system works smoothly with their workflow.

Three Conversations You Must Have With Your Tax Advisor

• Conversation 1 (September/October): 'I'm planning to switch accounting software on January 1. Which software do you recommend, and what data format do you need from me?'
• Conversation 2 (November): 'I've chosen [software name]. Here's what it exports. Does DATEV format work for you, or do you need something different?'
• Conversation 3 (December): 'I'm ready to migrate. Can you help me verify my opening balances are correct and that the first export looks right?'

DATEV Unternehmen Online: The Bridge Between You and Your Advisor

DATEV Unternehmen Online is a cloud platform that acts as a secure bridge between your accounting and your tax advisor's office. Even if you use lexoffice or sevDesk, you can export data to DATEV format and your advisor can import it into their DATEV workspace.

This solves a common friction point: it means your data never has to sit in email or on USB drives. Your advisor can securely access your DATEV export and work with it without you manually preparing reports.

What Exports Does Your Tax Advisor Need?

• Monthly or quarterly trial balance (Rohbilanz) showing all account balances
• Chart of accounts export with account descriptions and any cost center assignments
• Complete DATEV export file (if you're using DATEV-compatible software) or CSV export with full transaction detail
• Open items report showing unpaid invoices and outstanding payables
• Fixed assets report showing all depreciable assets and accumulated depreciation
• Bank reconciliation report showing how your accounting balances match your bank statements

Timeline: When to Inform Your Tax Advisor

• 3-4 months before migration (September): Initial conversation about switching and recommendations
• 2 months before migration (October): Final software decision and confirmation they can work with it
• 1 month before migration (December): Test export of data in new software; advisor reviews and confirms it looks right
• Migration week (December 31/January 1): Final cutover; advisor on standby if issues arise
• 1-2 weeks after migration: Advisor receives first export from new system and confirms everything is in order

GoBD Compliance During Migration: Requirements You Cannot Ignore

GoBD (Grundsätze zur Ordnungsmäßigkeit der Buchführung und Abrechnung Digital) is German law governing digital accounting. During a system migration, you're required to maintain specific compliance standards. Violating these carries penalties of €5,000 to €1,000,000+. This isn't theoretical—the German tax authority (Finanzamt) actively audits accounting system compliance.

What GoBD Says About System Changes

GoBD explicitly addresses system migrations. Key requirements:

• Data integrity: All data must remain unchanged when transferred. No data can be lost, altered, or corrupted in transit
• Completeness: All business transactions from the migration period must be recorded in the new system
• Immutability: Once data is created, it must not be modifiable or deletable (audit trails must show if any changes occur)
• Retention: Original data from the old system must be retained for 10 years, even after migration
• Legibility: Data must be readable and auditable in both the new system and archived copies
• Documentation: You must document the migration process and how the new system meets GoBD requirements

Verfahrensdokumentation: Your Migration Documentation

Verfahrensdokumentation is a formal document describing how your accounting system works and how it meets GoBD requirements. You need one for every accounting software you use—including after migration.

This sounds bureaucratic, but it's actually straightforward. Your Verfahrensdokumentation should include:

• Name, version, and vendor of your accounting software
• List of modules you use (invoicing, bookkeeping, payroll, etc.)
• Chart of accounts structure (Kontenrahmen) and how you use it
• How the system handles data entry, posting, and closing
• How the system exports data for external use (DATEV, tax return, etc.)
• Data backup and archiving procedures
• User access controls and audit trails

Most accounting software vendors provide a template Verfahrensdokumentation document. You download it, customize it for your business, and keep it with your tax documents. Your tax advisor will ask to see this during an audit.

10-Year Data Retention: What You Must Keep

GoBD requires retention of all accounting records for 10 years after the end of the calendar year in which the records were created. This means:

• All bookkeeping entries and journal entries from 2016-2026 must still be accessible if audited today (2026)
• Supporting documents (receipts, invoices, contracts) must also be retained
• When you migrate to new software, you cannot delete your old system's data—you must archive it
• Archived data must remain accessible and readable for audit purposes

Practically speaking: Export your complete old system database before migration, save it in multiple formats (native format AND CSV AND PDF for documents), and store it securely offline or in backup storage. Keep good records of what you archived and when.

Archiving: Export Formats for Audit-Proof Storage

When you archive your old system's data, you need to choose formats that will remain readable and auditable for 10 years. Best practices:

• Export journal entries as PDF (most readable, immutable, legally defensible)
• Export master data as CSV (universal format, viewable in any spreadsheet software)
• Export full DATEV format export (industry standard, professionally recognized)
• Create a complete system backup of your old software (as final fallback)
• Store in at least two locations: external hard drive + cloud backup (or two external drives)

Parallel Operation and Testing: Verify Before Fully Switching

One of the most valuable strategies during migration is parallel operation: running both systems simultaneously for a period of time. This gives you confidence that the new system is working correctly before you permanently abandon the old one.

Why 1-2 Months of Parallel Operation Makes Sense

Parallel operation means: from January 2 onward, you enter all transactions into BOTH your old system and new system. This is temporarily more work, but it's insurance. If something goes wrong in the new system, you still have the old system with complete records.

You run this parallel period for 1-2 months (not the entire fiscal year, which would be chaos). By end of February, you should be confident that the new system is working correctly. Then you can safely shut down the old system.

Test Bookings: What You Should Verify

During parallel operation, focus on verifying these specific items:

• Opening balances: Are January 1 account balances in the new system identical to December 31 in the old system?
• Sample invoices: Create test customer invoices in both systems—verify all fields post correctly
• Sample bills: Create test supplier invoices—verify posting to correct accounts
• Bank transactions: Verify that imported bank transactions match what actually appears in your bank account
• Tax calculations: Create sample invoices with VAT—verify that gross amount, tax, and net all calculate correctly
• Customer aging: Pull an open items report from the new system—verify it matches your outstanding invoices
• Chart of accounts: Verify that all account names, codes, and opening balances match between systems

Reconciliation: Comparing Balances Between Systems

At the end of your parallel operation period, pull a trial balance (Rohbilanz) from both systems. Every account balance should match exactly. If they don't, you've found a migration error before relying on the new system exclusively.

Common discrepancies and how to fix them:

• Rounding differences: If you're off by €0.01, it's a rounding issue in the migration. Usually inconsequential
• Missing transactions: If balances don't match by large amounts, transactions didn't migrate. Identify which ones and manually re-enter them
• Duplicate transactions: If balances are too high, transactions were entered twice. Delete the duplicates from the new system
• Account code mismatch: If a specific account is off, verify the mapping is correct. Some old systems and new systems number accounts differently

When to End Parallel Operation

You stop parallel operation when:

• Your trial balance matches perfectly between systems
• You've successfully processed at least one month of transactions in the new system without errors
• Your tax advisor has reviewed the first month's export and confirmed it looks correct
• Your team is confident using the new software's interface and workflows
• You've created your Verfahrensdokumentation and archived your old system's data

At that point, formally retire the old system. Archive it according to GoBD requirements and move forward with the new platform exclusively.

Specific Migration Scenarios: From Your Current System to Cloud

Different starting points require slightly different approaches. Let's cover the most common migration scenarios you might face.

Scenario 1: From Excel/Spreadsheets to Cloud Software

If your business is currently managing accounting in Excel, congratulations—you've identified the biggest inefficiency. Excel spreadsheets as your primary accounting system create massive compliance risk and manual work.

Migration from Excel is actually simpler than from traditional software because you don't have to de-couple from a complex system. Your challenge is structuring Excel data so it imports correctly into cloud software. Most cloud platforms have CSV import wizards designed for exactly this scenario.

Steps: Organize your master data (customers, suppliers, accounts) into clean columns in Excel. Create a separate sheet for transactions with consistent date, account, customer, amount fields. Use the cloud software's CSV import tool and carefully map Excel columns to the software's fields. Test with a sample month of data before importing everything.

Time required: 1-2 weeks of data organization, 1-2 hours of actual import. Total effort: much less than migrating from legacy software.

Scenario 2: From DATEV Desktop to Cloud Accounting

DATEV is a professional accounting platform used by many businesses and their accountants. Migrating away requires special attention because DATEV exports are comprehensive but proprietary.

The advantage: DATEV exports are clean and complete. Nearly every cloud software accepts DATEV format imports. The disadvantage: you lose the sophisticated reporting and fixed assets functionality that DATEV provides, so you're scaling down to simpler tools.

Steps: Export a complete DATEV export file (standard format), choose cloud software that accepts DATEV imports (lexoffice, sevDesk, or Billomat all do), and use their import wizard. Most handle DATEV imports automatically. Expect 2-4 hours of setup time. Your tax advisor will help verify the export looks correct.

Scenario 3: From Lexware Desktop to lexoffice Cloud

Lexware to lexoffice is a natural upgrade path (same company owns both). lexoffice specifically has import tools optimized for Lexware migrations. This is probably the smoothest migration path available.

lexoffice even offers a data migration service where their team handles the import for you. This costs €300-600 but ensures nothing goes wrong. If you have significant data volume (multiple years of transactions), it might be worth paying for.

Steps: Contact lexoffice and tell them you're migrating from Lexware. They'll provide a guided import or optionally handle it for you. Total time: 2-6 hours hands-on work if you do it yourself, or 1-2 weeks if you have lexoffice handle it.

Scenario 4: From sevDesk to lexoffice (or vice versa)

Migrating between two similar cloud platforms is straightforward because both use modern data standards. Both sevDesk and lexoffice support CSV imports and DATEV exports.

Steps: Export your data from sevDesk in CSV or DATEV format, then import into lexoffice using their import wizard. Most of the work is mapping fields correctly. Effort: 4-8 hours.

Scenario 5: International Migration (Foreign Software to German System)

If your business was originally set up with non-German accounting software (for example, you started in the US and moved to Germany), migrating to German-compliant software is mandatory, not optional.

Non-German software typically doesn't support GoBD compliance, German tax codes, SEPA payments, or the Kontenrahmen chart of accounts structure that German tax authorities expect. This migration is more complex because you're not just moving data—you're restructuring your entire bookkeeping system.

Recommendation: Hire a migration consultant or your tax advisor to help with this. The cost (€2,000-5,000) is justified because the structural differences are significant. Time required: 6-12 weeks.

Migration Complexity by Scenario

Understanding Migration Costs: Budget Reality

'How much will switching accounting software cost?' This is the question every business owner asks. The answer varies, but let's break down all costs—direct and indirect.

Direct Costs of Migration

• New software license (annual): €300-2000 depending on software and features chosen
• Migration tool or service: €0-1000 (free if you do it yourself, paid if you hire help)
• Tax advisor consultation for migration review: €300-1000 (typically 2-5 hours at €100-250/hour)
• Training for your team: €0-500 (time-based if done in-house, paid courses if external)
• Data archiving and backup storage: €50-200 for physical media or cloud storage

Indirect Costs to Consider

• Your time: 30-80 hours of your personal effort (value: €1500-8000 at typical business rates)
• Your team's time: 20-40 hours of staff time (value: €500-2000)
• Productivity loss during parallel operation (month of slightly slower bookkeeping)
• Potential revenue loss if you make errors during transition (rare but possible)

Cost Example: Real Numbers for a Typical SME

Let's say you run a 10-person B2B services company, currently using Lexware, switching to lexoffice on January 1. Here's what you actually spend:

This looks expensive until you consider the savings. If lexoffice automates 5 hours per week of manual bookkeeping (realistic for a move from desktop to cloud), you're saving approximately 260 hours per year. At €20/hour staff cost, that's €5,200 in annual savings—meaning the migration pays for itself in the first year.

ROI Calculation: When Migration Pays for Itself

Total migration cost: €6,100 (one-time) Monthly bookkeeping time saved: 5 hours × €20/hour = €100/month Annual savings: €1,200 Payback period: 6,100 ÷ 1,200 = 5 years Wait—that doesn't look great. But here's what changes the math:

• Reduced tax advisor fees: Better data exports mean fewer manual adjustments. Potential savings: €300-600/year
• Better cash flow management: Automated reconciliation catches payment errors earlier. Potential savings: €500-2000/year in avoided losses
• Faster closing and reporting: Month-end closes faster. Value: €1000-2000/year in time saved
• Business intelligence: Real reports and dashboards enable better decisions. Hard to quantify but significant
• Scalability: Cloud software costs €600/year regardless of growth. Desktop software often requires version upgrades, adding costs as you grow

When you factor in all these benefits, the migration typically pays for itself within 2-3 years, and the long-term savings compound annually.

Common Migration Mistakes and How to Avoid Them

Thousands of businesses migrate accounting software successfully every year. But some hit unexpected problems. Here are the mistakes to avoid:

Eight Common Migration Mistakes

• Mistake #1: Not involving your tax advisor until after migration. Your advisor might reject the new software's export format, forcing re-work. Solution: Involve them 3-4 months before migration.
• Mistake #2: Running dual systems for the entire fiscal year. This creates impossible reconciliation and tax compliance confusion. Solution: Run parallel operation for 1-2 months maximum, then fully cut over.
• Mistake #3: Migrating without proper data backup. If something goes wrong during import, you need the old system's data to restore from. Solution: Create complete system backups before starting migration.
• Mistake #4: Failing to verify opening balances. January 1 account balances are wrong, throwing off the entire year. Solution: Have your tax advisor verify opening balance export before going live.
• Mistake #5: Not documenting the migration process. Later, when audited, you can't explain how the transition happened. Solution: Create a simple migration checklist and document each step as you complete it.
• Mistake #6: Choosing software based on price alone instead of DATEV compatibility. You save €200/year on licensing but pay €1000/year in extra tax advisor fees. Solution: Let DATEV compatibility be a primary selection criterion.
• Mistake #7: Forgetting to archive old system data. After 3 years, you're audited and can't produce 2022 records because you deleted them after switching. Solution: Export and archive in multiple formats before deleting anything.
• Mistake #8: Skipping data validation during parallel operation. You don't discover the problem until you've already committed to the new system. Solution: Spend 2-4 weeks doing thorough testing and reconciliation.

Worst-Case Scenarios and Recovery

Even with careful planning, things occasionally go wrong. Here's how to recover from the worst-case scenarios:

• Scenario: Major accounts don't match between systems during parallel operation. Recovery: Stop. Don't go live. Identify the problem in the import. Likely causes: rounding errors, duplicate entries, or missing transactions. Fix in the new system and re-test before cutover.
• Scenario: Tax advisor rejects the data export format after migration. Recovery: You're now in the new system with no way back. Solution: Use your archived old system backup to re-export in the correct format. This adds 1-2 weeks of work but solves the problem.
• Scenario: You realize months into the new system that critical data didn't migrate (like fixed assets). Recovery: Reconstruct the missing data from your archived backup. This is time-consuming but possible. Prevention is better: validate all data categories before ending parallel operation.
• Scenario: A team member accidentally deletes data in the new system. Recovery: Most cloud accounting software has audit trails and can restore deleted data within 30 days. Contact your vendor immediately.

Your 12-Week Migration Roadmap

Here's the exact timeline to follow for a January 1 migration. Adapt it based on your specific situation, but use this as your baseline.

The 12-Week Timeline to Successful Migration

This is a realistic timeline for a small-to-medium business. If you have more complex data (international transactions, multiple entities, complex fixed assets), add 4-8 weeks. If you're a solopreneur with simple data, compress it by 4 weeks.

Before You Start: The Final Checklist

Use this checklist in the week before you begin your migration. If you can check all boxes, you're ready. If not, delay your start date until you can.

• You have written approval from your tax advisor to use your chosen software
• You have complete backups of your current system (multiple copies)
• Your new accounting software is set up, licensed, and ready to receive data
• You have exported your complete chart of accounts and verified it's error-free
• You have a clean list of all customers and suppliers with current contact information
• You have verified your opening balances (balance sheet as of Dec 31) with your accountant
• You have identified all open items (unpaid invoices to customers and suppliers)
• Your fixed asset register is complete and current
• You have determined your fiscal year cutover date and informed your team
• Your team has basic training in the new software
• You have created a simple one-page migration checklist for your records
• You have scheduled follow-up meetings with your tax advisor for Oct, Nov, Dec, and Feb

Additional Resources for Your Migration

You don't have to figure everything out alone. Here are resources that will help:

• Your chosen software's migration guides: Most vendors (lexoffice, sevDesk, etc.) publish detailed migration documentation on their websites
• Your tax advisor: They've helped dozens of clients migrate. Leverage their experience
• The software vendor's customer support team: Most offer free migration support during onboarding
• GoBD compliance documentation: The German tax authority publishes detailed guidance at www.finanzamt.de
• Industry associations: Your chamber of commerce (IHK/HWK) often has resources on accounting compliance
• This article: Bookmark it for reference during your migration process

Learn More About Modern Accounting Tools

Want deeper knowledge before choosing? Read our comprehensive comparisons of best accounting software in Germany 2026 and cloud vs. on-premise security considerations. Also explore how AI is automating German bookkeeping with intelligent receipt processing and categorization.

If you're newly founding your company, our tax advisor questionnaire guide helps you set up the right bookkeeping structure from day one—avoiding the migration headaches entirely.

Conclusion: Migration Is Simpler Than You Think

Switching accounting software feels intimidating because you're dealing with the heart of your business's financial records. But when you break it down into steps—audit → choose → plan → migrate → verify → archive—it becomes manageable.

Thousands of German businesses migrate successfully every year without losing data, violating GoBD compliance, or damaging their relationship with their tax advisor. You can be next.

Your Next Steps

• Step 1 (This month): Email your tax advisor. Ask which modern accounting software they recommend and whether DATEV compatibility matters for your situation.
• Step 2 (Next month): Choose your software based on their feedback. Secure a free trial or demo account.
• Step 3 (2 months from now): Schedule your migration timeline. If you're targeting January 1, start your 12-week plan now. If you're targeting a different date, adjust accordingly.
• Step 4 (Throughout): Use this guide as your reference. Check off the tasks as you complete them. Stay in regular communication with your tax advisor.
• Step 5 (January 2): Go live in your new system. The hard part is done.

Switching accounting software is an investment in your business's future. Modern cloud software will save you hours every week, improve financial visibility, ensure compliance, and scale with your business. The migration might take a few months, but the long-term benefits justify every hour of effort.

You've got this. Start the conversation with your tax advisor this week.