Does a valid format mean the Aadhaar is registered to someone?

No. The Verhoeff checksum only confirms the number is mathematically well-formed. It cannot tell you whether the Aadhaar was actually issued or who holds it, and this tool never contacts the UIDAI database.

Is my Aadhaar number sent anywhere?

No. The validator is privacy-first. The first-digit rule and Verhoeff check run locally in your browser with JavaScript — there are no network requests and your Aadhaar number never leaves your device.

India Aadhaar Format Validator — Verhoeff Checksum Check

Q: How is an Aadhaar number validated?

An Aadhaar is 12 digits. UIDAI's structural rules require the first digit to be 2–9 (it can never be 0 or 1), and the 12th digit is a Verhoeff check digit computed over all 12 digits using the dihedral-group multiplication, permutation and inverse tables. A number passes when the running Verhoeff checksum resolves to 0.

India Aadhaar format validator

Check whether an Indian Aadhaar number follows UIDAI’s published structure. An Aadhaar is 12 digits: the first digit must be 2–9 (it can never be 0 or 1), and the 12th digit is a Verhoeff check digit computed over all 12 digits using the dihedral-group multiplication, permutation and inverse tables.

The breakdown shows the first-digit rule and the Verhoeff checksum separately, so you can see exactly why a number passes or fails.

Privacy-first: every check runs in your browser. Nothing is uploaded, stored or sent to any server, and this tool does not query the UIDAI database.