Can you restart invoice numbers each year?

In short: Yes, you can restart invoice numbers each year, as long as every invoice you ever issue still has a unique reference. The usual way is to put the year in the number itself, so 2026-001 restarts at 2027-001 without ever colliding. What you must not do is reuse a bare number like 001 that you have already issued.

Invoice numbering looks like the most trivial part of freelancing, and then one January you find yourself wondering whether starting again at 1 is allowed, or whether your accountant will sigh.

Short answer: it is allowed, it is common, and there is a right way to do it. Here is the whole thing, including the case nobody writes about, which is moving to new software halfway through a sequence.

The one rule invoice numbers must follow

Almost every country’s rules come down to the same principle: every invoice must be uniquely identifiable, and the sequence must be traceable. In practice that means:

• Unique. No two invoices you have ever issued share a reference.
• Sequential. They run in order, so a missing one is visible.
• No unexplained gaps. If 2026-014 does not exist, someone should be able to find out why.
• Never reused. Once a number has been on a document that reached a client, it is spent forever, even if that invoice was cancelled.

Everything else, the format, the prefix, whether you restart annually, is yours to choose. For the rest of what belongs on the document, see what to put on an invoice.

Invoice numbering requirements vary by country, and some have specific rules for VAT invoices. Check your own, or ask an accountant.

So can you restart invoice numbers each year?

Yes, provided the year is part of the reference. That is the trick that makes it work.

• 2026-001 then 2027-001 is fine. The two are different references.
• 001 in 2026 then 001 again in 2027 is not. That is the same reference on two documents, which breaks the uniqueness rule.

Restarting annually is popular for good reasons. Your numbers stay short, it is obvious at a glance which year an invoice belongs to, and your first invoice of the year is not 1,247. It also makes year-end filing easier, because a year’s invoices are a contiguous block.

The alternative, never restarting, is equally valid. A single sequence running from 1 to whatever, forever, is simple and has no year boundary to think about. Pick one and stay with it.

Invoice numbering formats that work

Two things to avoid. Client-based numbering looks tidy but gives you several parallel sequences and no single order, which is exactly what the rules are trying to prevent. And dates alone, such as 16092026, collide the moment you raise two invoices in one day.

A practical note on padding: use 001 rather than 1. It sorts correctly in a folder and in a spreadsheet, and it quietly signals that you expect to send more than nine invoices.

What about gaps in the sequence?

Gaps are the thing people worry about most, and the worry is mostly misplaced. A gap is only a problem if it is unexplained.

The situation that creates one: you raise invoice 2026-014, send it, and the job falls through. You cannot delete it and hand 2026-014 to the next client, because two different documents would then share a number.

What to do instead:

• Cancel it, do not delete it. Mark it cancelled and keep the record. The number is spent, the gap is explained, and anyone reviewing your books can see what happened.
• If it had already been sent and needs reducing, issue a credit note against it rather than editing it. See how to issue a credit note.
• Carry on with the next number. Do not renumber anything to close the gap. Renumbering issued invoices is far worse than the gap.

Tally Crow supports this directly: invoices move forward through a single status flow, ending at paid, overdue or cancelled, and a sent invoice’s financial fields lock so one number can never produce two different PDFs.

How to switch invoicing software without breaking your sequence

This is the case that catches people out, and it is the reason most “should I switch?” questions get postponed to January.

You are on invoice 2026-046 in a spreadsheet, or in a tool you have outgrown, and you want to move now rather than wait five months. The fear is that the new tool will start you at 1 and leave you with two invoices numbered 2026-001, one in each system.

You do not have to wait for January. A tool worth using lets you set the starting number. In Tally Crow, invoice numbers are whole numbers that count up automatically, and you choose where they begin in your numbering settings before you issue your first invoice. If your last invoice was 2026-046, you would set the start to 47, because Tally Crow numbers do not carry a year or a prefix, and every invoice after that follows on without a duplicate or a gap. Once your first invoice is issued, the starting number locks and the sequence continues from your latest invoice.

A short checklist for moving mid-year:

1. Find your last issued number in the old system. The last one that reached a client, not the last draft.
2. Set the new tool’s starting number to the next one in the sequence.
3. Raise one test invoice and check the number is what you expected before you send anything.
4. Keep the old records. You still need them for the rest of the tax year, and for however long your country requires.
5. Do not re-import old invoices just to have them in one place, unless the new tool can do it without renumbering them.

Should credit notes use the same sequence as invoices?

No. A credit note is a different document type, so it gets its own number in its own sequence. Mixing them into one run makes it harder to tell at a glance what a reference points at, and it means a credit note eats a number that an invoice might otherwise have had.

The convention that reads best is a distinct prefix, so CN-2026-004 alongside invoice 2026-047. What matters is that each credit note is uniquely numbered and references the invoice it relates to. Tally Crow numbers credit notes in their own right, separate from your invoices, so the two never collide.

Set it once and forget it

Invoice numbering is the sort of thing that takes five minutes to get right at the start and hours to unpick later. Decide whether you restart annually, put the year in the number if you do, never reuse a number, cancel rather than delete, and keep credit notes in their own sequence.

Tally Crow numbers every invoice for you in one continuous sequence from the starting point you choose, locks the figures once an invoice is sent, and keeps credit notes in their own sequence, so the numbers stay clean without you thinking about it. One thing to know: it uses plain whole numbers that carry on from one year to the next, so it does not add a year prefix or restart each January. Starting free, with 2 invoices a month and no credit card. See features and pricing, or the freelance invoicing guide for the fundamentals.