The short version
Open Invoice settings and choose Numbering. Set a prefix and a pattern, check the example under it and select Save.
Prefix and pattern
The default prefix is INV and the default pattern is {prefix}-{YYYY}-{####}, which gives numbers like INV-2026-0001.
The prefix is 1 to 10 letters and digits. The pattern is up to 40 characters and can use these parts:
| Part | Becomes |
|---|---|
| {prefix} | Your prefix. |
| {YYYY} | The year, for example 2026. |
| {YY} | The short year, for example 26. |
| {MM} | The month, for example 03. |
| {####} | The invoice number. Use 3 to 8 hashes; the number of hashes is the minimum number of digits. |
A pattern needs exactly one {####}. Anything else is shown as typed. Under the fields, Timelydo shows Your first invoice will be (or Your next invoice will be) with a live example.
Starting from a number
Coming from another tool? Enter the number your next invoice should have in Next invoice number. It can only go up, never down, so no number is handed out twice. The highest value is 999,999,999.
No gaps and no reuse
A draft has no number. The number is given at the moment you send, so a draft you delete never leaves a gap. If a number would already be in use, Timelydo skips it. A voided invoice keeps its number and that number is never reused.
When the counter restarts
| Your pattern has | The counter restarts |
|---|---|
| {MM} | Every month |
| {YYYY} or {YY} | Every year |
| Neither | Never |
Changing the pattern starts or continues the counter that belongs to the new pattern.
Credit notes and estimates
Credit notes and estimates count on their own, so they never use up an invoice number.
| Document | Looks like |
|---|---|
| Credit note | CN-2026-0001 |
| Estimate | EST-2026-0001 |
They use your pattern with CN or EST in place of the prefix. If your pattern has no {prefix}, the letters CN or EST and a dash are put in front.
FAQ
Can I change the prefix later?
Why is there no number on my draft?
Can I set the next number lower?
Is the number of a voided invoice reused?
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