Good invoice number examples
- INV-2026-001: year plus a sequential number
- 2026-0042: compact annual sequence
- CLIENT-018: client code plus sequence when separate client numbering is practical
- JOB-1047-02: job number plus the second invoice for that job
Keep every number unique
Do not reuse an invoice number for a different transaction. If you cancel or correct an invoice, preserve the record and issue a clear replacement or credit document based on your accounting practices.
Do invoice numbers need to be consecutive?
Rules vary by jurisdiction and business type. A sequence is useful because gaps and duplicates are easier to detect. Ask your accountant or tax adviser what your records must show.
Starting a new year
You can continue one permanent sequence or begin a new annual sequence when the year is part of the number. Whichever method you choose, document it and use it consistently.