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Find the gap before your accountant does.
Paste your numbers. Every gap and duplicate, before the audit.
Paste your invoice numbers
Export the number column from your invoicing software or spreadsheet and paste it in.
A gap is what an audit asks about. In most of Europe the sequence has to be unbroken, so a missing number needs an explanation — and the usual explanation is a deleted invoice, which is the thing you are not supposed to do.
Runs in your browser
Nothing you type here is uploaded, logged, or stored. The file is built on your own machine and disappears when you close the tab.
Why gaps matter
In most of Europe the invoice sequence has to be unbroken. A missing number is not a filing quirk, it is a question: where is that invoice? The usual answer is that someone deleted a draft, which is the thing the numbering rule exists to prevent. Better to find it yourself than to have it found for you.
What it reads
It takes the trailing digits as the sequence and whatever precedes them as the prefix, so INV-2026-0007 and 2026/0007 both work. Consecutive gaps are collapsed into a range so twenty missing numbers read as one line. Anything that does not fit the pattern the rest share is listed separately rather than silently ignored.
What to do about a gap
If it was a cancelled invoice, the correct fix is a credit note that reverses it, not a deletion — the number stays used and the trail stays intact. If a number was skipped by accident, document why. Either way, write it down before you are asked.
Questions, answered
Is it free?
Yes, and there is no limit on how many you paste.
Is my list uploaded?
No. It is parsed in your browser and nothing is stored.
What formats work?
Anything ending in digits. Commas, spaces and new lines all separate entries.
How do I stop gaps happening?
Let the software own the numbering. weBiller assigns the next number on issue and will not let you delete an issued invoice.
Your next invoice takes a minute.
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