Test an Aadhaar number’s Verhoeff check digit on your device; shown masked, never saved
Runs in your browser. Nothing you type is sent anywhere. Updated on 25 Oct 2026.The last of an Aadhaar number’s 12 digits is a Verhoeff check digit, which catches every single mistyped digit and every swap of two neighbours. Enter a number and this page tests that digit and the reserved first digit, then shows only the last four. The number is not sent, not stored and never put in a share link. Whether it was issued is answered only by UIDAI’s Verify Aadhaar.
The page opens with Aadhaar selected; type the 12-digit number into the box.
Read the headline: Valid Aadhaar format and check digit, or Check digit wrong.
Go down the checks for 12 digits, First digit is 2 to 9 and Verhoeff check digit.
Click outside the box and the number is shown masked, with only the last four digits visible.
Use Verify Aadhaar on UIDAI’s myAadhaar, linked below, to confirm it was issued.
Most Indian identifiers have a structure you can check before a form is submitted. This page reads six of them, tells which one you pasted from its shape, names each part, and tests the check digit where one exists and is published.
| ID | Length | Built from | Check digit tested here |
|---|---|---|---|
| GSTIN | 15 | State code, PAN, entity number, Z, check | Yes, base 36 |
| PAN | 10 | Series, holder type, name initial, number, check | No, formula not published |
| Aadhaar | 12 digits | 11 random digits and a check | Yes, Verhoeff |
| IFSC | 11 | Bank code, 0, branch code | None defined |
| UPI ID | Varies | Name, @, handle | None defined |
| PIN code | 6 digits | Region, sub-region, district, post office | None defined |
Nothing you type leaves your device. An Aadhaar number is shown masked to its last four digits once you leave the box, and no value is saved in the browser. Share links carry the ID type, plus the value only for an IFSC or a PIN code; an Aadhaar number, PAN, GSTIN or UPI ID never goes into a link.
The rest of the article, and all 6 questions about India ID Number Validator, are on the India ID Number Validator page.
No. A correct format and check digit only prove the number was copied without a typo. Whether it was issued, is active, or belongs to a given person or business is known only to the issuer: use Search Taxpayer on the GST portal, Verify Your PAN on the Income Tax e-filing portal, or Verify Aadhaar on UIDAI's myAadhaar.
Each of the first 14 characters becomes a number from 0 to 35 (digits, then A as 10 up to Z as 35). Alternate characters are multiplied by 1 and 2, each product adds its quotient and remainder by 36 to a total, and the check character is 36 minus the total's remainder, modulo 36. The page shows every step.
The twelfth digit of an Aadhaar number is a Verhoeff check digit, the scheme UIDAI's numbering design chose because it catches every single wrong digit and every swap of two neighbouring digits. Numbers starting with 0 or 1 are reserved, so a resident's Aadhaar begins with 2 to 9. Checking needs no internet connection.
No. Every check runs in your browser and the page makes no network request with what you type. An Aadhaar number is shown masked to its last four digits, nothing typed is kept in browser storage, and share links never include an Aadhaar number, PAN, GSTIN or UPI ID.
Still stuck? Ask about India ID Number Validator and anybody who knows can answer. No account needed.
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