Feature

Set your invoice number format once. Increment forever.

Pick the format you want (year-based, sequential, prefix-based), set the starting number, and every new invoice picks up the next one in sequence. Override on any individual invoice when your accounting system or a specific client requires a different number.

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Custom invoice numbering is the rule that says every invoice your business issues carries a unique, sequential identifier. Most jurisdictions require it: the IRS, HMRC, the EU VAT directive, and Canada's CRA all flag invoice number gaps in audits. JupiterInvoice lets you set the format and the starting number once. Every new invoice you create picks up the next number automatically, with the format you chose. You can override any individual invoice's number when you need to (for example, to match a number your accounting tool has already assigned). The feature is free, no paid tier required.

Why invoice numbers matter more than people think

A skipped or duplicated invoice number is the kind of thing that nobody notices for years and then becomes a real problem during a tax audit, a sales-tax registration, or due diligence. Tax authorities expect a continuous sequence. Auditors expect to be able to reconstruct your billing history. AP teams expect a predictable format so they can route invoices through their workflow.

The wrong way to manage invoice numbers is to type them by hand each time, which is how you end up with INV-0042 followed by INV-0044 because someone got distracted. The right way is to pick a format once and let the system increment for you.

What you get

Pick the format that fits your business

Year-based (INV-2026-0001), pure sequential (INV-0001), prefix-based (your initials, your business code), or a custom shape your accountant prefers. The format is yours, not ours.

Auto-increment on every new invoice

The next invoice you create picks up the next number in your chosen format. No typing, no remembering where you left off, no risk of accidental duplicates.

Override per invoice when you need to

If your accounting system has already assigned a number, or a specific client requires a different identifier, edit the number on that single invoice. The auto-increment continues from your sequence on the next one.

Free, with everything else

Custom invoice numbering is part of the free product. No paid tier, no upsell. Most invoicing tools gate this behind a Pro plan; we don't.

Common formats and when to use each

→Year-based: INV-2026-0001. The most common and the easiest to audit. Pads to four digits so you can issue up to 9,999 invoices per year before re-padding. Resets the counter at the start of each year.
→Pure sequential: INV-0001. Fine for low-volume businesses. Counter never resets. Pick the padding (3, 4, or 5 digits) based on your projected lifetime invoice count.
→Prefix-based: ACME-0001. Useful if your accountant or AP teams sort invoices by issuer prefix. Combine with a year segment (ACME-2026-0001) for the cleanest audit trail.
→Date-based: INV-20260306-001. Useful for high-volume businesses issuing many invoices per day. Each day's counter resets, the date carries the sequencing.

If you want to test a format before committing, the free invoice number generator previews any format and shows you what the next 10 numbers would look like.

Custom invoice numbering FAQ

Are sequential invoice numbers legally required?

In most jurisdictions, yes. The IRS, HMRC, the EU VAT directive, and Canada's CRA all require that invoices issued by a registered business carry a unique, sequential identifier. Auditors specifically check for gaps. If you void an invoice, keep the number on file with a 'voided' note rather than skipping it.

Can I change the format mid-year?

Yes, but be deliberate. Changing format mid-sequence creates two parallel series in your records, which auditors will ask about. The cleanest moment to change format is at the start of a new tax year, with a documented note in your records explaining the switch.

What happens if I delete an invoice?

Deleting a sent invoice creates a gap in your sequence, which is what auditors flag. Best practice is to mark the invoice voided rather than delete it, so the number stays on file with a clear note. JupiterInvoice keeps voided invoices in the audit trail with version history intact.

Can I have different number formats for different clients?

Per-customer or per-document-type prefixes (Q-001 for quotes, INV-001 for invoices, separate sequences per client) are not yet built. Today the format is set per sender profile and applies to every invoice issued from that profile. If you need different sequences for different entities, multiple sender profiles are the workaround.

What if my accounting tool has already assigned a number?

Override the number on the individual invoice. Type the number you want in the invoice number field; it saves on that single invoice and your auto-increment sequence continues unaffected on the next new invoice.

Does JupiterInvoice charge to use this?

No. Custom invoice numbering is part of the free product alongside everything else. Every sent invoice carries a small 'Powered by JupiterInvoice' footer; nothing else is gated.

Last updated June 1, 2026