Aadhaar Number Validator
Finance & Indian IDsCheck if an Aadhaar number follows the official 12-digit format issued by UIDAI. Verifies structure only, not registration or authenticity.
What is a Aadhaar?
The Aadhaar Number Validator checks whether a given 12-digit number follows the structural format mandated by the Unique Identification Authority of India (UIDAI). Aadhaar is India's national biometric identity system — every resident who has enrolled receives a unique 12-digit number linked to their fingerprints, iris scans, and demographic information.
The format rule is straightforward: the number must be exactly 12 digits, and the first digit must be between 1 and 9. Numbers are often written with spaces between each group of four digits (for example, 2345 6789 0123), but the underlying value is always 12 continuous digits. This validator accepts both spaced and unspaced entry.
It is important to understand what this validation does — and does not — confirm. A format check tells you that the number is structurally plausible, which is useful for catching obvious typos before submitting a form. It does not tell you whether the number is registered in UIDAI's database, whether it belongs to the person presenting it, or whether it is currently active. For any purpose requiring genuine authentication, use UIDAI's official APIs or the resident portal.
For Indian residents, Aadhaar is relevant across dozens of touchpoints: income tax e-filing (PAN–Aadhaar linking is mandatory), direct benefit transfers, pension scheme enrolment, and government portal logins. A typo in the 12-digit number causes application rejections and delays. Running a quick format check before submission prevents many of these avoidable errors.
You can use this tool alongside the PAN Number Validator when preparing documents that require both identifiers.
How to use this Aadhaar calculator
- Type or paste the Aadhaar number into the input field. You can enter it with spaces (e.g. 2345 6789 0123) or without (234567890123) — both formats are accepted.
- The validator runs automatically as you type. You do not need to press a button.
- Check the Valid or Invalid badge below the input field.
- If the result is Invalid, read the error message to understand what needs correcting — for example, whether a digit is missing or whether the number starts with a zero.
- Once the badge shows Valid, the number is structurally correct and ready to use in forms that require Aadhaar.
- To validate a different number, clear the field and enter the new value.
Formula & Methodology
Format rule: An Aadhaar number must satisfy all three conditions: 1. Exactly 12 characters (after removing spaces) 2. All characters are digits (0–9) 3. The first digit is 1–9 (never 0) Expressed as a regular expression (after stripping spaces):/^[1-9][0-9]{11}$/Valid example:2345 6789 0123— 12 digits, first digit is 2. Invalid example:0234 5678 9012— fails because the first digit is 0. Invalid example:2345 6789 012— fails because only 11 digits are present. This tool does not implement the Verhoeff checksum algorithm, which UIDAI uses internally during enrolment. The checksum details are not publicly documented in a form that would allow reliable third-party verification, and implementing an approximation could produce misleading results. Structural format validation is the only check that can be reliably performed without access to UIDAI's systems.