International · Hungary
Adóazonosító jel validator.
Check whether a Hungarian personal tax identification number (adóazonosító jel) has 10 digits, starts with 8 and ends in the correct check digit. It checks format and check digit only. Everything runs in your browser.
How it works: multiply digit 1 by 1, digit 2 by 2, and so on up to digit 9 by 9, add the products and divide by 11. The remainder must equal the 10th digit. If the remainder would be 10, that serial is never issued, so no valid number looks like that.
Inputs
Result
Enter a number and press Check.
How the adóazonosító jel is built
The adóazonosító jel is the tax identification number Hungary gives to private individuals. Under Annex 1 of Act XX of 1996 it has ten digits. The tax authority generates it; you do not choose it.
| Digits | Meaning |
|---|---|
| 1 | Always 8, marking a private individual |
| 2 to 6 | Number of days elapsed between 1 January 1867 and the date of birth |
| 7 to 9 | Randomly generated serial separating people born on the same day |
| 10 | Check digit: sum of digits 1 to 9, each multiplied by its position, divided by 11; the remainder |
Worked example with a constructed number: 8449251230. The products are 8, 8, 12, 36, 10, 30, 7, 16 and 27, which add to 154. 154 divided by 11 leaves remainder 0, matching the last digit. This example is built for illustration and is not a real person's number.
What the tool shows for the date
The day count in digits 2 to 6 is shown as a date by adding that many days to 1 January 1867, following the statute's wording. The checksum, not the date, decides whether the number passes. A day count that lands in the future is flagged.
Checks format and check digit only
A passing result means the ten digits are consistent with the statutory rule. It cannot confirm the number was issued by the Hungarian tax authority (NAV) or who holds it. This page does not query any register.
Sources
1996. évi XX. törvény a személyazonosító jel helyébe lépő azonosítási módokról és az azonosító kódok használatáról (Hungarian Act XX of 1996), 1. számú melléklet, retrieved October 2026: ten digits, constant 8, day count since 1 January 1867, serial, and the weighted mod 11 check digit, including that a serial giving remainder 10 is not issued.
Frequently asked questions
What is an adóazonosító jel?
It is the 10-digit tax identification number Hungary assigns to private individuals. It always starts with 8 and ends in a check digit.
How is the adóazonosító jel check digit calculated?
Multiply each of the first nine digits by its position (1 to 9), add the products, divide by 11 and take the remainder. That remainder is the 10th digit.
Why can a number never end up with a remainder of 10?
Remainder 10 does not fit in one digit, so the law says a serial that would produce it is not issued.
Does a valid result mean the number is real?
No. It only means the digits follow the statutory rule. Only the Hungarian tax authority can confirm that a number was issued.
Is the number I type sent anywhere?
No. The check runs in your browser and nothing is transmitted, stored or logged.
Checksum only, not a lookup
This tool checks the number's format and check digit entirely in your browser. A valid result does not prove the number was issued or belongs to anyone, and it does not query any official register. Nothing you type is transmitted or stored.