Under section 209 e of the Finnish VAT Act (arvonlisäverolaki), an invoice must show the invoice date, a unique sequential number, the seller's Business ID (Y-tunnus), the names and addresses of the seller and the buyer, what was sold and how much, the delivery date, the taxable amount per VAT rate, the VAT rate and the amount of VAT. If the invoice total including VAT is at most €400, simplified particulars are enough. This article goes through every item, and what a missing one actually costs you.

Which invoice details are mandatory in Finland?

The mandatory details are the same whether your company is a toiminimi (sole trader) or an osakeyhtiö (Oy, limited company), and whether you invoice from software or by hand.

This covers ordinary sales. Special cases, such as sales of new means of transport, the margin scheme and investment gold, need an extra note of their own.

What are simplified invoice particulars?

Simplified particulars (kevennetyt laskumerkinnät) are enough when the invoice total including VAT is at most €400.

A simplified invoice shows the invoice date, the seller's name and Business ID, the quantity and type of goods or the type of services, and the VAT amount per rate or the taxable amount per rate. The buyer's details are not needed.

Simplified does not mean careless. If the buyer is a business that deducts VAT, it needs the VAT amount per rate. Without it, the receipt does not work as a voucher for their deduction.

What is a sequential invoice number and why does it matter?

The sequential number is the invoice number. It identifies one invoice and nothing else, and the numbers run in an unbroken series.

You can run several series, for example one for sales invoices and one for credit notes, or one per location. What matters is that no numbers are missing from a series and no number is used twice.

A gap in the series is one of the first things a tax auditor notices, because it raises the question of where the missing invoice went. The usual cause is simple: invoices were made in two places, each with its own numbering. That is why invoice numbering and retention belong in one system.

How do you split the taxable amount by VAT rate?

The taxable amount (veron peruste) is the sales price excluding VAT. It is shown separately for each VAT rate on the invoice, never as a single total.

Example. A café invoices a business customer for an event with catering and hired audio equipment. Catering is taxed at the reduced 13.5% rate, equipment rental at the general 25.5% rate.

The invoice total is €1,183.00. If the whole amount were taxed at the general rate, the VAT would be €255.00 and the invoice €72.00 too high. A wrong rate costs more than a wrong amount, because it repeats on every similar invoice. The full list of what falls under each rate is in our article on Finnish VAT rates in 2026.

Does an invoice need a payment term and late interest?

A payment term and a late interest note are not mandatory particulars under the VAT Act, but in practice you need both.

Without them, the invoice is valid for tax purposes but weak as a contract, and in a dispute the question moves to contract terms that a small company rarely has in writing.

How long a term you can give and what the late payment interest rate is in 2026 are covered in our article on payment terms and late payment interest in Finland.

Are the requirements different for an e-invoice?

No. The mandatory particulars apply to an e-invoice (verkkolasku) exactly as they do to a paper or PDF invoice. A structured format does not replace the content: the sequential number, Business ID, delivery date, taxable amount per rate and VAT rate are all still required. They simply sit in fields instead of free text.

What an e-invoice is, and when a customer can require one, is explained in our article on e-invoicing in Finland.

What happens if a mandatory detail is missing?

A missing detail does not cancel the sale, but it creates a problem for the buyer, and through the buyer for you.

The buyer needs the particulars as the voucher for their VAT deduction. If details are missing, they can ask for a new invoice, and your payment waits as long as the new invoice takes. A business customer's accounts payable system may also reject the invoice automatically.

On your side, one missing address is not a problem in a tax audit. A systematic gap across all your invoices is.

Frequently asked questions

Is the company name enough without an address?

Not on a full invoice. The VAT Act requires the names and addresses of both the seller and the buyer. On an invoice of at most €400, simplified particulars apply and the buyer's details are not needed.

Does a Finnish invoice have to show the Y-tunnus?

Yes. The VAT identifier of a VAT-registered seller, which for domestic sales is the Business ID (Y-tunnus), is a mandatory particular.

What is the €400 invoice limit in Finland?

It is the limit for simplified particulars. When the invoice total including VAT is at most €400, a shorter set of details is enough.

Can I choose my own invoice numbers?

Yes, but they must be sequential and unique. Random numbers do not meet the requirement.

Do I have to show the delivery date if it is the same as the invoice date?

Yes. The delivery date is its own mandatory particular, even when it matches the invoice date.

Why is an invoice more than a message to your customer?

The mandatory particulars are not bureaucracy for its own sake. They are the details that the buyer and the Finnish Tax Administration (Verohallinto) both need, so the invoice can be processed without follow-up questions.

NoCFO is the all-in-one AI-native finance platform for entrepreneurs and founders. Invoicing and bookkeeping run on the same platform, so an invoice you send is already a voucher in your books, with no separate transfer. The platform does the routine work and you or your accountant stay in control: NoCFO suggests, a person reviews and approves.

For the whole picture, from payment terms to year end, read our guide to invoicing in Finland. To send an invoice with every particular in place, start free at nocfo.io.

Sources (checked 29 September 2026)

• Verohallinto: Laskutusvaatimukset arvonlisäverotuksessa (mandatory particulars under section 209 e, simplified particulars up to €400)

• Verohallinto: VAT rates (25.5%, 13.5% and 10% in 2026)