Invoice number generator
Choose a prefix and sequence to generate professional invoice numbers.
Suggested number: INV-1001
How it works
Prefix + Year + Sequence, for example INV-2026-1001
Choose a prefix
Use something short like INV, or your initials.
Set the sequence
Start from your next unused number.
Pick a format
Use the same format on every invoice so numbers stay in order.
Frequently asked questions
Quick answers about this calculator.
Do invoice numbers have to be sequential?
In many countries, yes. Each number should be unique and follow on from the last one without gaps.
Should I include the year?
It is optional, but a year makes invoices easier to sort and lets you restart the sequence each year.
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Free, no sign-up and ready to download as a PDF.