Every invoice needs a number that exists exactly once. Zirko assigns it for you — you only decide what it looks like. Do this before your first invoice, not after your twentieth.
Settings → Accounting → Number ranges. All office roles can see the settings; only Office – Admin can change them.
Eight ranges, one per document type
| Range | Default |
|---|---|
| Customers | K- from 10001 |
| Projects | P- from 101 |
| Quotes | A- from 101 |
| Cost estimates | KV- from 101 |
| Order confirmations | AB- from 101 |
| Delivery notes | LS- from 101 |
| Invoices | R- from 101 |
| Credit notes | G- from 101 |
Each range has three settings: format, start value and minimum length. Zirko calculates the “Next value” column from them — you cannot type into it.
Building the format
Zirko fills in five placeholders when a document is created:
{number}— the running number, padded to the minimum length{yyyy}and{yy}— the year, four or two digits{mm}and{dd}— month and day, two digits
So R-{yyyy}-{number} with a minimum length of 5 gives R-2026-00101. If you leave out {number}, Zirko appends the running number at the end.
Allowed are letters, digits, the characters ( ) { } [ ] / \ - and single spaces; 40 characters at most. The minimum length runs from 3 to 7 and pads with zeros — 101 becomes 00101.
No two ranges may produce the same number
A format consisting only of {number}, or with no identifier of its own, is rejected: the number would be digits alone, and nobody could tell an invoice from a quote. Zirko reports two ranges that could overlap when you save.
When numbers have already been issued
Once a range has counted, the last value issued appears below the field. Issued documents keep their number — always. Your change only affects what is created afterwards.
Zirko refuses to save if the new count would run into a number already issued. The message names the document that carries it. That is deliberate: the same invoice number twice is a mistake you cannot cleanly repair later.