Invoice numbering & series

Invoice numbers look like an administrative detail, but they carry legal weight. This article explains what Latvian law actually requires and how Fakts assigns numbers.

What the law actually requires

A common belief is that invoice numbers must be gapless, that invoice 2025/003 must be immediately followed by 2025/004 with no gaps. That is not what the law says.

What this means in practice: a gap you can explain is lawful, and in an audit a brief note on the skipped number is sufficient. Fakts avoids most gaps anyway: an invoice gets its number only when it is issued, so a deleted draft never uses one up.

How Fakts numbers invoices

For each series, Fakts maintains a sequential counter in the database using row-level locking. This means that even if two invoices are issued at the same moment, they receive different numbers, so duplicates are impossible by design. A number is assigned when the invoice is issued, not when the draft is saved, so invoices are numbered in the order they are issued.

The invoice form shows which number comes next, but a draft holds no number until it is issued. You can type your own number if you need to, and the draft keeps it. When your number fits the format, the automatic numbers that follow continue after it.

You define the number format under Settings → Number series: what the number starts with (for example INV), whether it shows the year, the separator, and how many digits the counter has. Examples: INV-26-001 or R/2026/001. Your next number is shown beside the choices.

Series and yearly resets

Fakts numbers three kinds of document, each in its own series: invoices, credit notes and quotes. Each series has its own counter; the format is shared.

The counter starts again at 1 every January. Keep the year in the format, so numbers from different years never repeat, stay short, and keep your bookkeeping in order.