Aadhaar
Aadhaar (Unique Identification number)
Also known as: Aadhaar, Aadhaar card, Aadhaar number, UIDAI number, Indian national ID
Aadhaar is a 12-digit unique identity number issued to residents of India and is the world's largest biometric ID system. Backed by demographic and biometric data in the UIDAI repository, it is used for welfare delivery, banking KYC, and tax linkage, with the Aadhaar app (which replaced mAadhaar in 2026 and adds face authentication and QR-based offline sharing) and DigiLocker extending it to mobile.
Aadhaar number format
12 digits, printed in groups of four, never starting with 0 or 1
- •Digits 1 to 11: randomly generated, carrying no encoded demographic meaning by design
- •Digit 12: check digit
Verhoeff algorithm checksum. UIDAI requires masked Aadhaar or Virtual ID for most relying-party use rather than storage of the full number.
About 134 crore (1.34 billion) live Aadhaar holders per the Government of India, with more than 145 crore Aadhaar numbers generated in total (UIDAI dashboard, September 2026)
Domestic
Privacy and trust
The Supreme Court in Puttaswamy (2018) upheld Aadhaar for welfare use while striking down mandatory private-sector and bank/SIM linkage, and the surveillance and welfare-exclusion debate remains active.
Identity verification providers
Independent identity verification vendors that support documents like this for KYC and onboarding. Exact document coverage varies by provider and region, so confirm support before relying on it.
Aadhaar: frequently asked questions
- Is Aadhaar proof of citizenship?
- No. Aadhaar is proof of identity and address for residents of India. It does not confer citizenship and is explicitly residency-based.
- How can I use Aadhaar without exposing my actual number?
- Use a Virtual ID, a temporary revocable 16-digit number generated on the UIDAI website or in the Aadhaar app, share a masked Aadhaar or QR-based offline credential, and turn on biometric lock.