Home Rodné číslo Czechia
Czechia Rodné číslo validator
How the Rodné číslo format works
- Format
- 9 or 10 digits
- Example
- 7103192745
Things to watch for
- 10-digit numbers are valid when the full number divides evenly by 11 (with a narrow 1954-1985 historical exception); 9-digit numbers, issued before 1954, carry no check digit at all and are accepted on format alone
- Written with a slash (YYMMDD/SSSS) which this tool's normalization strips before checking — enter it with or without the slash
- The first 6 digits encode a date of birth (month offset by 50 for women) — we validate format and checksum only, never the date, and never store what you enter
^[0-9]{9,10}$A rodné číslo (birth number) is the identifier Czechoslovakia introduced in 1954 and the Czech Republic has used ever since, issued to residents and printed on ID cards, health insurance cards, and most official paperwork. It’s conventionally written with a slash — YYMMDD/SSSS — separating a date-of-birth prefix (with the month offset by 50 for women) from a serial and check portion, though the digits underneath are what actually get validated.
What sets a rodné číslo apart from most check-digit schemes on this site is that there’s no separate weighted check digit at all. Instead, a 10-digit number is valid if the entire 10-digit value divides evenly by 11 — the check is baked into the number as a whole rather than computed from a formula and appended. A narrow exception covers numbers issued in a specific 1954-1985 window, where the first nine digits leave a remainder of 10 when divided by 11 and the final digit is 0. Numbers from before 1954 have only 9 digits and no check at all, a leftover of the pre-1954 numbering system that this tool accepts on format alone.
How this validator works
The slash is cosmetic — this tool strips whitespace before checking, so YYMMDD/SSSS or the bare 9-or-10-digit form both work. For 9 digits, only the length and digit pattern are checked. For 10 digits, the tool confirms the full number divides evenly by 11, or falls back to the 1954-1985 exception. Everything runs in your browser; nothing is transmitted or stored.
What a pass doesn’t tell you
Passing this check confirms the digits satisfy the divisibility rule (or, for 9-digit numbers, just the format) — not that the number was ever issued or is still active. Only the Czech population register can confirm that.
Scope: this page covers rodné číslo format and checksum validation only — not identity or registration lookups, and never the embedded date of birth or sex.
Content last reviewed 2026-08-09.
Rodné číslo FAQ
How is a rodné číslo's check digit calculated?
Unlike a single weighted check digit, a 10-digit rodné číslo is valid whenever the full 10-digit number divides evenly by 11. A narrow historical exception applies to numbers issued between 1954 and 1985: if the first nine digits divide by 11 with a remainder of 10, a final digit of 0 is also accepted.
Why do some rodná čísla have only 9 digits with no check at all?
Czechoslovakia introduced the check-digit rule in 1954. Numbers issued before that — 9 digits, formatted YYMMDD/SSS — carry no check digit whatsoever and are accepted on structure alone: 9 digits in the right shape, nothing more to verify.
Does a valid rodné číslo confirm someone is on file with Czechia's population register?
No. Passing the divisibility check only confirms the digits are arithmetically consistent — it doesn't confirm the number was ever issued or that it's still active. Only the Czech population register administered by the Ministry of the Interior can confirm that.