This tool validates two common Colombian identity numbers. The cédula de ciudadanía is the personal national ID — a plain serial with no public check digit, so only its format can be confirmed. The NIT (Número de Identificación Tributaria, the tax ID) does carry a modulo-11 verification digit defined by the DIAN, which this tool can compute and check. It is built for catching data-entry errors, and never contacts any registry.
How it works
For a cédula, the tool confirms only that the number is plausibly formed: 6 to 10 numeric digits. There is no algorithm to prove a specific cédula is genuine.
For a NIT, it computes the verification digit (DV). Reading the base number right to left, each digit is multiplied by the DIAN weight series 3, 7, 13, 17, 19, 23, 29, 37, 41, 43, 47, 53, 59, 67, 71. The products are summed, then taken modulo 11:
remainder 0 or 1 → DV = remainder otherwise → DV = 11 − remainder
It then tells you the DV, or whether a DV you supplied matches.
Example
For the NIT base 900373115, applying the weights right to left and reducing modulo 11 gives a verification digit of 3 — so the full NIT is 900.373.115-3. A cédula like 1020304050 (10 digits) passes the format check, but cannot be confirmed beyond that.
It is privacy-first: every check runs locally in your browser and the number is never sent anywhere or verified against any registry.