Invoice Number Generator
Set a prefix, the next number, and how many digits to generate a clean invoice number.
How to use this calculator
- 1Set a prefix such as INV- or your initials.
- 2Enter the next number in your sequence and how many digits to pad to.
- 3Copy the generated number — the following numbers are shown so you can keep the sequence going.
How the Invoice Number Generator works
Good invoice numbering is simple, sequential and unique: a prefix such as INV- followed by a padded number (INV-0001, INV-0002, and so on) with no gaps. Many tax authorities actually require invoice numbers to run in an unbroken sequence, so a consistent format keeps you compliant and makes invoices easy to find and reconcile.
A prefix can encode a year or client code (2026-0001) as long as the numeric part keeps counting up. Some businesses start higher than 1 so their first invoices don’t reveal that they are brand new. Generate your next number here, then create the invoice itself in seconds with Aviy.
Ready to bill for it?
Create a professional invoice in one sentence with Aviy’s free AI invoice generator.
Create an invoice freeFrequently asked questions
How should I number invoices?
Use a simple, sequential, unique system — e.g. INV-0001, INV-0002 — with no gaps. Many tax authorities require invoice numbers to be sequential and unique.
Can invoice numbers have letters?
Yes — a prefix like a client code or year (2026-0001) is fine, as long as the numeric part stays sequential and each invoice number is unique.
Do I have to start at 1?
No. Start wherever you like — some businesses start higher (e.g. 1000) so early invoices don’t signal that you are brand new.
Related reading
Lash Technician Invoice Template: Free Guide and Examples
A free lash technician invoice template with worked examples, deposit and no-show policy tips, and what to itemize for fills, full sets and lash products.
Continue Reading
Invoicing for Remote Workers Worldwide: The Complete 2026 Guide
A practical guide to invoicing for remote workers worldwide - currencies, taxes, payment methods and templates to help you get paid faster across borders.
Continue Reading
Best Invoice Software for Teams (2026 Buyer's Guide)
Compare the best invoice software for teams in 2026. Roles, approvals, audit trails and shared billing explained - plus how to choose the right fit fast.
Continue Reading
The End of Manual Invoicing: How AI Is Replacing the Old Way
The end of manual invoicing is here. See what is replacing spreadsheets and templates, why it matters, and how freelancers and small businesses can adapt.
Continue Reading
Best Invoice Software for Growing Companies (2026 Guide)
Compare the best invoice software for growing companies in 2026. See the criteria that matter, what to avoid, and how to pick a tool that scales with you.
Continue Reading