Free tax reference finder
Find out which assessment number belongs to a payment reference, check the 16 digits or calculate the payment reference from an assessment number. This free calculation tool uses no AI: all processing follows fixed rules and stays local in your browser.
Free calculator
Runs entirely in your browser
Check digit
Modulus 11 recalculated
Number structure
Eleven test and tax code verified
Privacy
No input sent or stored
In three steps
Step 1
Spaces, dots and dashes can stay. The calculator tidies up the input first.
Step 2
Length, number structure, tax code, eleven test and modulus 11 are checked deterministically.
Step 3
View the tax type, period and derivable numbers, with a description for the bookkeeping.
Check a payment reference
A payment reference from the Dutch Tax Administration consists of 16 digits. The first digit is a check digit; the remaining positions contain, among other things, part of the BSN or RSIN, a code for the tax type and details about the year or period. Looking only at the number of digits is therefore not enough.
The calculator recalculates the check digit with modulus 11 and validates the BSN or RSIN with the eleven test. The tax code is then checked against the public specification. An error is therefore not silently converted into an apparently usable assessment number.
Number structure
The two numbers serve a different purpose. The assessment number identifies the return, assessment or decision. The payment reference is the numeric payment reference your bank and the Dutch Tax Administration use when processing the payment.
| Characteristic | Payment reference | Assessment number |
|---|---|---|
| Format | 16 digits | 9 digits, 1 letter and 7 digits |
| Purpose | Linking a payment automatically | Identifying a return, assessment or decision |
| Where to find it | Letter, payment details or bank statement | Letter, return or decision |
| Check | Modulus 11 check digit | BSN/RSIN with middle letter and JAVO part |
Coverage
The tax code in the payment reference determines which conversion rule applies. The table shows the categories from specification 1.5 that this tool supports deterministically.
| Code | Tax type | Support |
|---|---|---|
| 0x / 6x | Payroll taxes | Return and additional assessment |
| 1x / 5x | Turnover tax (VAT) | Return and additional assessment |
| 70 / 73 | Income tax | Assessments, including for conscientious objectors |
| 74, 80–84, 92–96 | Corporation tax | Assessments for organisations with an RSIN |
| 75 | Health Insurance Act | Income-related Zvw contribution |
| 23–28 | Benefits | Benefits and the associated penalty decisions |
| 76 / 78 / 87 / 88 | Motor vehicle tax | HSB/MOA outside the random range |
| 85 / 86 / 97 | Other levies | Eurovignette, LIR and pollution levy |
For certain environmental levies, protective assessments and a series of motor vehicle tax numbers, the Dutch Tax Administration creates a random reference. Without the non-public lookup table there is no reliable formula for those.
Honest about the limits
The official specification warns that more and more assessment numbers do not get a payment reference that can be derived by formula. A modulus 11 check can then still show that the 16 digits are internally valid, but not which assessment number belongs to them. This tool reports that difference explicitly.
Safe calculation, without AI
The conversion runs entirely in JavaScript on your own device. The calculator uses no server request, AI model, account, localStorage or URL parameter for your input and result. Close or refresh the page and the data is gone.
An independent aid, not affiliated with the Dutch Tax Administration. No rights can be derived from the result.
Frequently asked questions
A payment reference is the 16-digit reference the Dutch Tax Administration uses to link a payment automatically to the right return, assessment or decision. It is also called a payment characteristic or, in searches, a tax reference.
In the calculator, choose Check a payment reference, paste the 16 digits and click Convert and check. The tool first validates the check digit and then shows only the details that can be derived under the public calculation rules.
Some of the references are assigned at random. The link is then held in internal tables that are not public. An unknown tax code, an incorrect check digit or a type outside version 1.5 can also produce a specific error message.
No. The input and the result stay in this browser, do not end up in the URL and are not sent to Agentancy or kept locally. Only the ordinary, non-substantive page view falls under the website's analytics choice.
No. Every conversion follows fixed, verifiable rules from the public specification Betalingskenmerk bepaling 1.5. The result is not predicted or filled in by a language model.
No. Agentancy is an independent software supplier for accountancy firms. This free tool is an aid; if in doubt, always check payment details in the letter, in Mijn Belastingdienst or in the official search tool.
Yes. Choose the second mode of the calculator and enter the full number: 9 digits, 1 middle letter and 7 digits. Categories that cannot be derived by formula are deliberately refused, so that no plausible but incorrect reference is created.
Do not simply make the same payment again. Keep the proof of payment and follow the current explanation from the Dutch Tax Administration; the right next step depends on exactly what was missing or went wrong with the payment.
Source and last checked
Based on the public Specificatie Betalingskenmerk bepaling 1.5. Content and official example calculations checked on 23 July 2026.
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