Aadhaar Validator

Validate an Aadhaar number using the Verhoeff algorithm — the official checksum used by UIDAI.

Enter 12 digits — auto-formatted with spaces
🔒 This check runs entirely in your browser. Your Aadhaar number is never sent anywhere.

About Aadhaar number structure

An Aadhaar number is a 12-digit random number issued by UIDAI. Unlike PAN or GSTIN, it does not encode any personal information in its digits — the number is essentially random, with the last digit being a Verhoeff checksum.

First digit

Cannot be 0 or 1. This is a UIDAI rule to distinguish Aadhaar numbers from other numeric identifiers.

Digits 2–11

Randomly assigned. No state, district, age, or gender information is encoded in these digits.

Last digit (checksum)

Computed using the Verhoeff algorithm, a dihedral group-based checksum that can detect all single-digit errors and most transpositions.

Frequently asked questions

What is the Verhoeff algorithm?

The Verhoeff algorithm is a checksum algorithm developed by Dutch mathematician Jacobus Verhoeff in 1969. It uses a multiplication table based on the dihedral group D5, a permutation table, and an inverse table. It detects all single-digit errors and all adjacent transposition errors, making it more robust than Luhn (used in credit cards).

Does a valid checksum mean the Aadhaar exists?

No. A valid Verhoeff checksum means the number has the correct format and is mathematically plausible, but it does not confirm that UIDAI has actually issued this number to anyone. Only UIDAI's systems can verify that.

Why can't the first digit be 0 or 1?

UIDAI reserves numbers starting with 0 and 1 to avoid confusion with other numbering systems. All valid Aadhaar numbers begin with digits 2 through 9.

Can I verify my Aadhaar on this tool?

You can verify the format and checksum here. For official verification (confirming the number is registered with UIDAI), use the official UIDAI portal at myaadhaar.uidai.gov.in or the mAadhaar app.

Is it safe to enter my Aadhaar number here?

Yes. This tool runs entirely in your browser — no data is transmitted to any server. However, be cautious about entering your Aadhaar on any website. For official purposes, only share your Aadhaar with trusted government portals.