The Slovak DIČ (daňové identifikačné číslo) is the 10-digit tax identification number issued by the Financial Administration (Finančná správa). Prefixed with SK, it becomes the IČ DPH VAT identification number used across intra-EU trade and e-invoicing. This free tool applies the official format rules and the modulo-11 checksum in your browser so you can catch errors before filing.
How it works
A valid Slovak DIČ must satisfy several rules at once:
- Drop an optional
SKprefix and any separators, leaving exactly 10 digits. - The first digit must not be
0. - The third digit must be one of
2, 3, 4, 7, 8, 9. - The whole 10-digit number, read as an integer, must be divisible by 11.
To compute the modulo-11 result safely for a 10-digit number, the tool folds each digit in turn (remainder = (remainder * 10 + digit) mod 11), which avoids any floating-point precision issues.
Example and notes
Take 2022749619. Its first digit 2 is non-zero, its third digit 2 is in the allowed set, and the number is divisible by 11 with remainder 0 — so it is reported as a valid DIČ. Change any single digit and the mod-11 test will almost always fail, which is exactly what catches data-entry mistakes.
A passing checksum confirms internal consistency only. It does not confirm the entity is VAT-registered or active in VIES — only the official Finančná správa or VIES service can do that. Everything here runs locally, so the number never leaves your device.