If you run an Estonian OÜ, issuing compliant invoices is not optional. Estonian invoice requirements are defined by the VAT Act (§37) and the Accounting Act, and mistakes can lead to rejected accounting entries, VAT corrections, or unnecessary questions from the Tax and Customs Board (EMTA).
Whether you are VAT-registered or not, whether you invoice EU or non-EU clients, every Estonian company must follow specific invoicing rules. This 2026 guide explains exactly what must be included on an invoice, when invoices must be issued, how reverse charge works, and how long invoices must be stored.
Why invoicing matters for Estonian companies
Every invoice becomes part of:
• Your bookkeeping
• VAT reporting (if registered)
• Corporate income tax calculations
• Your annual report
Incorrect invoices often cause:
• Delays in VAT returns
• Rejected accounting entries
• Additional accountant corrections
• Confusion during audits
For e-residents managing companies remotely, invoicing errors are one of the most common compliance issues we see at Unicount.
Mandatory invoice requirements in Estonia (VAT Act §37)
Under Estonian VAT law, every sales invoice must include specific mandatory information. These requirements apply to all taxable persons and, in practice, to all OÜ companies issuing invoices.
A compliant Estonian invoice must include:
- A unique invoice number following a logical sequence
- Date of issue
- Date of supply (if different from issue date)
- Seller’s legal name and registered address
- Seller’s registry code
- Seller’s VAT number (if VAT-registered)
- Buyer’s name and address
- Buyer’s VAT number (for B2B EU transactions)
- Description of goods or services
- Quantity or scope of services
- Unit price (excluding VAT)
- Taxable amount by VAT rate
- VAT rate applied
- VAT amount in euros
- Total payable amount
If the supply is zero-rated or reverse charged, the invoice must include a clear legal reference (e.g., “Reverse charge – Article 44 VAT Directive” or relevant Estonian VAT Act provision).
Let’s break the requirement down:
1. Invoice identification
• Unique serial number
• Date of issue
• Date of supply (if different from issue date)
Invoices must follow a logical sequence. Gaps in numbering raise accounting questions.
2. Seller details
• Full company name (exactly as in Business Register)
• Registered address
• Registry code
• VAT number (if VAT-registered)
3. Buyer details
• Full name or company name
• Address
• Registry code (if legal entity)
• VAT number (required for 0% intra-EU supply)
If issuing reverse charge or 0% intra-Community supply, the buyer’s valid EU VAT number must be included and verified.
4. Description of goods or services
• Clear description
• Quantity or scope
• Unit price (excluding VAT)
• Any discount (if not included in price)
Vague descriptions such as “consulting services” without period or scope may be challenged.
5. VAT breakdown
• Net amount per VAT rate
• Applied VAT rate (24%, 13%, 9%, or 0%)
• VAT amount in euros
• Total payable amount
If VAT-exempt or reverse charge applies, the invoice must reference the legal basis.
If your company is not VAT-registered, you must not add VAT at all, not even 0%.
Invoice requirements for non-VAT registered companies in Estonia
Many founders assume that VAT rules only apply to VAT-registered businesses. That is incorrect.
Even if your Estonian company is not VAT-registered:
- You must still issue proper invoices
- You must not add VAT
- You must not display 0% VAT unless legally justified
- All mandatory commercial information must still be included
Non-VAT registered companies simply omit the VAT section. However, invoice numbering, transaction details, and accounting accuracy remain mandatory under the Accounting Act.
When must an invoice be issued in Estonia?
A VAT-registered company must issue an invoice:
• Within 7 days of supplying goods or services
• For all taxable supplies
Even if not VAT-registered, invoices must still meet accounting standards. The seller is legally responsible for invoice compliance, even if invoicing is outsourced.
Reverse charge and intra-community supply invoices in Estonia
For B2B services provided to EU clients, reverse charge rules often apply. For cross-border EU services and goods:
To apply 0% VAT:
- The buyer must be VAT-registered in another EU country
- The VAT number must be verified in VIES
- The invoice must include both VAT numbers
- The invoice must state that reverse charge applies
- For intra-Community supply of goods:
- The buyer must be VAT-registered in another EU Member State
Common notation example:
“Reverse charge under Article 44 / VAT Directive 2006/112/EC”
Failure to reference the legal basis may result in VAT being treated as domestic 24%.
Can someone else issue the invoice?
Yes.
Estonian law allows:
• Third-party invoicing
• Self-billing (buyer issues invoice)
However:
• There must be written agreement
• Seller remains legally responsible
• Self-billing invoices must clearly state “self-billing”
Electronic invoicing rules in Estonia (2026 update)
Estonia operates a progressive e-invoicing framework.
Currently:
- E-invoicing is mandatory for B2G (business-to-government) transactions
- B2B e-invoicing is voluntary
From July 1, 2025:
- Companies registered as e-invoice receivers may request structured e-invoices
Full mandatory B2B e-invoicing is expected in the coming years.
Invoices must be stored for 7 years from January 1 following the financial year.
Electronic invoices:
- Do not require a digital signature
- Must remain accessible
- Must be reproducible in readable format
Accepted formats:
• Estonian XML standard
• European EN 16931 standard
No electronic signature is required for e-invoices.
Invoice storage and record retention requirements in Estonia
Under the Accounting Act:
- All invoices must be stored for 7 years
- Storage may be digital
- Documents must be accessible upon request
- Archiving outside Estonia is allowed if quick access is guaranteed
Missing invoices or incomplete records may invalidate expense deductions and create tax risk.
Manual invoice vs accounting software
You can create invoices:
• In Word or Canva
• In invoicing software
• Through integrated accounting tools
Manual invoicing works initially but increases risk of:
• Incorrect VAT calculations
• Numbering gaps
• Formatting errors
• Missing reverse charge references
Integrated systems reduce correction costs later.
Common invoicing mistakes Estonian companies make
- Adding VAT without being VAT-registered
- Forgetting reverse charge wording
- Using incorrect VAT rates
- Missing invoice numbers or broken numbering sequence
- Invoicing without checking EU VAT numbers
- Failing to retain transport proof for EU goods
Most problems appear during annual report preparation, not at the time of issuing the invoice.
How Unicount Ensures Compliant Invoicing for Estonian Companies
At Unicount, invoicing is aligned with accounting from day one.
Our accounting setup ensures:
- Correct VAT application
- Automated compliance with Estonian VAT rules
- Proper invoice sequencing
- Direct integration into bookkeeping
- Accurate annual report preparation
This reduces correction cycles and avoids unnecessary EMTA inquiries.
In a Nutshell
An invoice in Estonia is not just a PDF.
It is a regulated accounting document tied to VAT law and reporting.
Getting it right from the first invoice:
• Prevents corrections
• Saves accounting costs
• Reduces audit risk
• Keeps annual reporting smooth
If you are unsure whether your invoices are compliant, it is easier to fix it early.
FAQ: Estonian Invoice Requirements
Do I need to issue invoices if my Estonian company is not VAT registered?
Yes. All companies must issue invoices for business transactions. VAT registration only affects whether VAT is added.
What VAT rate applies in Estonia in 2026?
Estonia currently applies 24%, 13%, 9%, and 0% VAT rates depending on the type of goods or services.
How long must invoices be kept in Estonia?
Invoices must be stored for 7 years from January 1 following the financial year.
Is e-invoicing mandatory in Estonia?
It is mandatory for B2G transactions. B2B mandatory e-invoicing is expected in the coming years.
Can I issue invoices in foreign currency?
Yes. However, VAT amounts must be declared in euros in accounting records.
What happens if my invoice is non-compliant?
The invoice may need correction. Incorrect VAT handling may result in additional tax liability or EMTA inquiries.
Do I need to verify my EU client’s VAT number?
Yes. If applying reverse charge or zero VAT, verification through VIES is required.
