Invoice Number Generator: Sequential Invoice and Quote IDs

Invoice numbering: building a continuous, compliant number series

In France every invoice carries a unique number based on a chronological, continuous sequence (General Tax Code, annex II, art. 242 nonies A). The tool combines a prefix, the year, the month and a zero-padded counter, for example FAC-2026-10-0001, and generates 5 to 50 consecutive numbers to copy or export as CSV.

How the number is built

Number = prefix (without its trailing separator) + separator + year (4 or 2 digits) + separator + month (MM, optional) + separator + counter padded to 2 to 6 digits. The year (the current one by default), month, separator, padding and starting number can be set.

Examples (October 2026)

• Default setting, prefix FAC-: FAC-2026-10-0001, FAC-2026-10-0002…
• Standard: F-2026-10-0001 (D for quotes, AV for credit notes, BC for purchase orders).
• Monthly: FAC/26/10/001.
• ISO yearly: INV-2026-00101, a 5-digit counter starting at 101.
• Minimal: 2026-0001.

The CSV export lists, for each number, the document type, the reference year-month and the status “Disponible”.

Rules to follow

• No gaps or duplicates within a series, and no number deleted or inserted afterwards; a wrong invoice is corrected with a credit note that cites the original invoice.
• Separate series (per site, per invoicing method, etc.) are accepted when the way the business operates justifies them, ideally with a distinct prefix for each series.
• The continuity rule covers invoices and credit notes; quote numbering is free.

Tool limits

• It does not remember the last number issued and never resets the counter, even with the monthly preset: you enter the starting number yourself.
• When the counter outgrows its width (99 with 2 digits), the number gets longer (F-2026-10-100) and alphabetical sorting breaks: allow 4 digits or more.

The site's invoice generator handles the content and totals of each invoice. These are French rules.

Sources and dates: French General Tax Code, annex II, art. 242 nonies A, via the Entreprendre Service Public page on mandatory invoice mentions (checked 11/08/2026); tax guidance BOI-TVA-DECLA-30-20-20-10 on separate series (checked 14/10/2026).

Frequently Asked Questions

How should invoices be numbered under French rules?

Each invoice gets a unique number, allocated in chronological order, with no gaps or duplicates (General Tax Code, annex II, art. 242 nonies A). A format such as FAC-2026-10-0001 works, provided no number is ever deleted or reused.

Can a business use several invoice number series?

Yes, when the way the business operates justifies it: several sites, several invoicing methods or customer categories. Each series must remain continuous, and a distinct prefix per series avoids confusion.

How do you cancel an invoice that already has a number?

You do not delete it or reuse its number: you issue a credit note, itself numbered in a continuous series, that cites the original invoice. The tool's Standard preset offers the AV prefix for credit notes.

How many digits should the counter have?

Enough never to exceed the chosen width: 4 digits cover 9,999 invoices per series. Beyond that the number gets longer (F-2026-10-100 after F-2026-10-99 with 2 digits) and alphabetical file sorting no longer follows the real order.

Is this tool really free?

Yes, all tools on Kristools are 100% free and accessible without registration.

Is my data protected?

Yes. All processing is performed directly and securely inside your browser. No personal data is sent to our servers.