Free tools
Invoice number generator
Design a number format that suits you and see right away what the next invoice numbers look like, also after New Year.
Everything is calculated in your browser. Nothing is sent or stored.
How it works and what to know
An invoice number consists of a prefix (for example INV or F), optionally the year and a sequence number of fixed length. That gives numbers like INV-2026-0001.
Every invoice number must be unique and you use consecutive numbers in one or more series. Starting over each year is possible if the year is in the number so numbers stay unique.
You never reuse a number once issued. If an invoice is wrong, correct it with a credit note instead of reusing the number.
Indicative, not tax advice
Frequently asked questions
Why does an invoice need a number?
According to the invoice requirements of the Dutch Tax Administration every invoice has a unique number. You need it for your VAT records and for your customer’s VAT deduction.
May I use several number series?
Yes, you may use one or more series of consecutive numbers, as long as each number occurs only once. Think of a separate series for credit notes.
Does the year have to be in the invoice number?
It does not have to be, but it is handy. A common format is the year followed by a sequence number. The year also lets you start over every year.
Can I start numbering again every year?
Yes, provided numbers stay unique. So put the year in the number. Without a year, number 1 would exist in two years at once, and this generator warns you about that.
What if I skipped a number or made a mistake?
Keep numbers consecutive and never issue an issued number again. Correct a wrong invoice with a credit note and make a new invoice with the next number.
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