Free invoice number generator

Invoice number generator and format planner

Preview invoice numbers using a prefix, optional year, separator, starting sequence, and padding. No signup required. Preview only — keep the sequence aligned with your existing invoice records.

Invoice number pattern

Build an invoice number format

Prefix Optional; up to 12 letters and numbers. Example: INV or STUDIO. Separator Choose a character between each part. Four-digit year Optional. Enter the year you want to show in the pattern. Starting sequence The first number to show in the example sequence. Number padding For example, four digits displays 1 as 0001.

Readable structure

What each pattern part means

A prefix can identify the document series, an optional year can make periods easier to recognize, and padding gives sequence values a consistent width. For example, prefix INV, year 2026, hyphens, and four-digit padding produces INV-2026-0001.

If you include a year, update it when you intentionally start using the next year's pattern.

Understand the fields: Invoice number, invoice date, and PO number.

Keep your own record

Keep your existing sequence in sync

Compare the preview with invoices you have already issued, cancelled, corrected, imported, or created elsewhere. Maintain the sequence in the accounting or record-keeping system you actually use.

If you change the format mid-series, record when the new pattern starts so the sequence stays easy to follow.

Numbering rules

Check the pattern fits your requirements

Invoice-numbering requirements vary by jurisdiction, document type, business, and record-keeping system. Before issuing an invoice, make sure your chosen pattern keeps the required sequence clear and traceable.