Birth number generator
Generate fictional but mathematically valid Slovak/Czech birth numbers for testing.
Birth number generator
This tool generates birth numbers (rodné číslo) that are structurally and mathematically valid but belong to no real person — they exist purely as test data for QA suites, form validation demos, sample databases and training material. Every number follows the same public rules a real one does: the first six digits encode a date of birth as YYMMDD, and for numbers from 1954 onward a check digit is appended so the whole value passes the standard mod-11 checksum. Numbers dated before 1954 use the older 9-digit form, which never carried a check digit.
Choose a year range and the generator only draws birth dates from inside it, so you can produce a batch of numbers for adults, for a specific decade, or split across the format change in 1954 to test both code paths at once. Pick "male", "female" or "both" for sex — the month field is offset by 50 for a female birth, exactly as the real encoding does, and "both" mixes the two randomly across the batch. Set how many numbers to generate, and choose whether the output separates the date and the serial with a slash (900101/1234) or runs all the digits together (9001011234).
Because the check digit is computed for every 10-digit number, output from this tool passes the same validation logic as TextArray's own birth number validator — paste a batch straight in there to confirm, or wire it into automated tests that need to assert your form correctly accepts (or rejects tampered variants of) a well-formed rodné číslo. The tally under the output also breaks the batch down by how many numbers came out male and how many female.
Everything runs locally in your browser using the Web Crypto API for randomness — nothing is sent anywhere, logged or stored, and no output here was ever assigned to an actual person. Use it strictly for testing and development, never to represent a real individual's identity.