Invoices and documents · 2 min read

Invoice numbering

How Taxorio automatically numbers invoices, what separate sequences it keeps for advances, credit notes and tax documents for a payment, where to reset the counter, and why numbering must be continuous with no gaps.

Automatic numbering

Taxorio automatically assigns every new invoice a number from your numbering sequence. The format is YYYYXXXX (year and a four-digit sequential number, no separator) — for example 20260001, 20260002, and so on. The year updates automatically at the start of each year and the sequential number restarts from 0001.

The numbering sequence is continuous — Taxorio always continues from the highest number used so far that year, so no duplicates arise. You can see and change the sequential number the sequence is currently at in Settings → Invoicing → Invoice counter; it can only be moved up, never below a number that's already in use.

Both the document number and the variable symbol can be overwritten by hand — when issuing the invoice, and for an unpaid invoice also later via Edit. Once an invoice is paid, the form can no longer be opened at all: first use More actions → Clear payment.

Separate numbering sequences

Taxorio keeps separate numbering sequences for different document types, so they never mix. Each sequence has its own fixed prefix:

  • Invoices (standard and final): 20260001
  • Proforma invoices: ZAL20260001
  • Credit notes: DOB20260001
  • Tax documents for an advance: DDZ20260001

These sequences and their format are fixed — numbering runs automatically and needs no configuration.

Continuity of numbering and legal requirements

Neither the VAT Act (§29) nor any other tax regulation strictly mandates a particular numbering format, but it does require invoice numbers to form an unbroken chronological sequence. VAT payers are specifically flagged on this rule during audits:

  • There must be no gaps in the numbering sequence — a skipped number can raise the tax authority's suspicion.
  • Numbers must be assigned chronologically.
  • A voided invoice should be documented with a credit note, not deleted.
⚠️ Careful: Only an unpaid proforma invoice with no linked documents can be deleted — tax documents are never physically deleted in Taxorio; they're cancelled or corrected with a corrective document instead. Even deleting a proforma invoice leaves a gap in the sequence, so reach for cancellation instead.

Imported invoices and foreign numbers

An invoice carried over from another system keeps its original number (say, 007/2026) — that's the only way the document stays identical to what the client and the accountant have on file. Your counter isn't derived from a number like that: it follows Taxorio's own internal sequence exclusively, so a foreign format won't throw off your next number and your invoicing settings stay saveable.