Sequential series, with no reused numbers
Each invoice carries a number inside its series. The series moves forward. A number already issued is not recycled.
A series follows an order
Numbering runs forward inside the series. You can keep separate series if each one is identified, for example one per activity. What does not fit is repeating, in that series, a number that already went out. That order is what a billing record can read later. The context is in VeriFactu for autónomos.
The next number, and the corrective invoice
Factura Fácil assigns the next number in the series when you issue, and it does not use a spent number again. If the invoice is wrong, you do not rewrite it in place: you issue a corrective invoice that points at the original. If you void an invoice whose record was already sent to the Tax Agency, that void creates a cancellation record. For an autónomo, use of an adapted system is in a trial period until 1 July 2027.
- Each number in the series is used once.
- A correction is a corrective invoice, not a rewrite of the old one.
- Voiding a record already sent leaves a cancellation record.
Common questions
Can I start again at 1 each year?
You can open a series for the year and number it from the start. Inside that series, a number is not repeated.
Does deleting the invoice give me the number back?
Do not reuse that number. If it was already issued, the correction is a corrective invoice. If the record had been sent, voiding it creates a cancellation record.
Official sources
Informational text reviewed on 26 September 2026. It is not tax advice and does not replace the Spanish Tax Agency or your accountant. Deadlines, rates, and forms can change.