Lithuania
Lithuania's SAF-T system, i.MAS, modernizes tax administration with comprehensive reporting requirements for VAT transactions, transport documents, and accounting data.
Modules
Lithuania's SAF-T implementation, known locally as i.MAS (Intelligent Tax Administration System), consists of three distinct modules:
| Module | Description | Filing requirement | Deadline |
|---|---|---|---|
| i.SAF | VAT invoice register with sales and purchase information | Mandatory monthly | 20th day of the following month |
| i.VAZ | Transport/consignment documents for domestic goods movement | Mandatory before goods movement | Prior to transport |
| i.SAF-T | Comprehensive accounting data including general ledger, customer/supplier information, assets, and inventory | On-request only | Within 30 days of request |
While i.SAF requires regular monthly submissions from all VAT-registered entities, the full i.SAF-T module is only submitted when specifically requested by tax authorities during audits or investigations.
Possible penalties
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Failure to submit i.SAF: Penalties ranging from €200 to €6,000 depending on severity and frequency
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Late submission: Administrative penalties based on the delay period
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Inaccurate data: Penalties proportional to the tax impact of errors
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Repeated violations: Increased penalties for systematic non-compliance
Special considerations
- Non-residents
- Foreign entities with Lithuanian VAT registration must comply with i.SAF monthly reporting requirements. However, only resident businesses are required to maintain i.SAF-T readiness for on-demand submission.
- Small businesses
- The implementation of i.SAF-T was phased based on business size:
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From January 1, 2019: Companies with revenue exceeding €45 million in 2018
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From January 1, 2020: Companies with revenue between €3 million and €45 million in 2019
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From January 1, 2021: Companies with revenue less than €3 million in 2020
Currently, all businesses must comply regardless of size.
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- Industry specific requirements
- All industries must comply with the same technical requirements. There are no industry-specific variations in the i.MAS system.
File structure
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i.SAF structure
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Header: contains metadata about the reporting entity and period
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Master file: Contains data from registers of issued and received VAT invoices
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Source documents: Details of each invoice with optional payment information
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Format: XML following Lithuania's specific schema
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i.SAF-T structure
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Header: Metadata about the file, company, and reporting period
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Master files:
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Chart of accounts
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Customer and supplier information
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Product and service classifications
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Tax tables
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Unit of measure tables
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Analysis codes
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General ledger entries: All accounting transactions during the period
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Source documents: Detailed information about invoices, payments, and other transactions
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Assets: Fixed asset register and movement information
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Inventory: Stock item details and movements
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VAT classification codes
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Lithuania requires specific coding of transactions based on VAT treatment
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Proper classification is essential for correct reporting
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Both domestic and cross-border transactions require appropriate coding
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Lithuania's i.SAF-T implementation follows the OECD standard but includes country-specific adaptations to align with local tax requirements.
Submission requirements
- Deadlines
- The i.MAS system has different deadlines for each module:
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i.SAF (VAT invoice register): Must be submitted by the 20th day of the month following the reporting period. This is a strict monthly requirement for all VAT-registered entities.
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i.VAZ (Transport documents): Must be submitted before the domestic movement of goods begins. This is an immediate requirement tied to each transport operation.
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i.SAF-T (Full accounting data): Must be submitted within 30 days of receiving a request from tax authorities. There is no regular filing schedule; submissions are only required during audits or investigations.
Unlike some other countries, Lithuania does not currently require periodic submission of the full i.SAF-T file, but businesses must maintain their systems in a state of readiness to generate compliant files when requested.
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Filing formats & methods
- File format: XML only, following specific Lithuanian schemas
- Character encoding: UTF-8
- File size limits: 4 MB for manual upload; 5 MB for automated submission
- Submission methods:
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Electronic Declaration System (EDS): Primary submission portal
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API Integration: For automated submissions from ERP systems
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Manual upload: Through the VMI portal for smaller businesses
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Lithuania requires strict adherence to its XML schemas. Files that do not conform to the specifications will be rejected.
Authentication
- Electronic Banking Authentication
- Using credentials from Lithuanian banks
- Smart-ID
- Digital identity solution
- Mobile signature
- Mobile-based digital signature
- Qualified electronic signature
- EU-compliant digital signature
Each submission receives a digital stamp from the tax authority as confirmation of receipt.
How to file
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Prepare your i.SAF/i.SAF-T file:
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Extract required data from your accounting system
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Ensure proper VAT classification of all transactions
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Format according to the required XML schema
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Validate file structure before submission
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Validate the file:
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Use the VMI's validation tools available on their website
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Check for format errors and data consistency
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Address any validation issues before proceeding
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Generate a validation report for your records
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Access the Electronic Declaration System (EDS) portal:
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Go to https://deklaravimas.vmi.lt
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Log in using your authentication method
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Go to the appropriate i.MAS section
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Upload and submit:
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Select the correct reporting period
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Upload your XML file
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Review submission details
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Complete the submission process
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Alternative: API submission:
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For businesses with high transaction volumes
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Implement direct system-to-system communication
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Ensure proper error handling and confirmation processing
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Maintain logs of all submissions and responses
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Confirmation and follow-up
The Electronic Declaration System (EDS) provides a two-stage confirmation process for i.MAS submissions. First, you receive an immediate technical receipt confirmation. Later, usually within 24 hours, you receive a content validation confirmation. Each confirmation includes a unique document number, submission timestamp, and digital stamp from the tax authority.
You can check the status of your submission through the "Document Status" section of the EDS portal. If validation fails, you will receive notification of errors with the option to submit corrections.
If errors are detected in your submission, you must correct and resubmit within the timeframe specified by the tax authority. For i.SAF, corrections should be submitted as soon as possible, as this data affects your VAT compliance status.
Archive expectations
All supporting documents and underlying data must be retained for tenyears from the end of the financial year. This includes all transaction data that forms the basis of i.SAF and i.SAF-T submissions.
Electronic records must remain accessible throughout the retention period, with clear audit trails maintained between documents, entries, and reports. System changes or upgrades must not compromise access to historical data.
Lithuanian tax authorities may conduct detailed cross-checks between i.SAF monthly submissions and the i.SAF-T data provided during audits. Any inconsistencies can trigger additional scrutiny. Your systems must maintain the ability to regenerate historical reports and demonstrate data consistency across time periods.
Archived data must be secured against unauthorized changes while remaining accessible for audit purposes. Companies must document their accounting systems and processes to explain how data is generated and maintained.