Rekenbox · Checks
Invoice amounts and duplicate number checker
Check entered invoice amounts, VAT and duplicate invoice numbers.Clarity for your records
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Understand your result
How this tool works
Copy supplier, number, date and amounts from your invoices. The tool compares net, VAT and gross amounts and looks for duplicate invoice numbers in the entries. It does not read a PDF or photo here; accurate transcription remains the starting point.
Common questions
Does a duplicate number mean an invoice was paid twice?
No. It flags a possible duplicate entry. It has no bank payments or complete supplier ledger to establish duplicate payment.
How are mixed VAT rates checked?
With mixed rates selected, the tool checks the total. It does not infer how much of the net amount belongs to each rate.
Which details do you need?
- Invoices
Limits of this tool
- Copy amounts from your invoices. A one-cent rounding difference is reported separately. Mixed rates check only the total.
Year: 2026 · Version 2026.1
Sources for this tool
- Belastingdienst — factuureisen · calculation source checked 2026-09-04
Prepared by the Rekenbox product team at Winstwaker. The listed source references and calculation version make the method traceable. Report a content error Last updated: 2026-09-04. Rekenbox is a product by Winstwaker. The tool applies a calculation model to your inputs; a result or paid report is not a personal assessment by an adviser.