How is a Canadian SIN validated?

A SIN is 9 digits and uses the Luhn (mod-10) algorithm. Every second digit from the left is doubled, any product over 9 has 9 subtracted, all digits are summed, and the total must be divisible by 10. The first digit also indicates the registration region — for example 9 is reserved for temporary residents and 0 is never issued.

Does a passing Luhn check mean the SIN belongs to a real person?

No. The Luhn check only confirms the number is mathematically well-formed. It cannot tell you whether the SIN was actually issued or who it belongs to, and this tool never contacts any government system.

Is my SIN sent anywhere?

No. The validator is privacy-first. The Luhn check runs locally in your browser with JavaScript — there are no network requests and your SIN never leaves your device.

Canada SIN Validator — Social Insurance Number Check (Luhn)

Canada SIN validator

Validate a Canadian Social Insurance Number (SIN) using the official Luhn (mod-10) check digit algorithm. The tool doubles every second digit, normalises products over 9, sums the digits and confirms the total is divisible by 10.

It also reads the registration region from the first digit — for example 4–5 is Ontario, 2–3 is Quebec, 7 is British Columbia and Yukon, and 9 is reserved for temporary residents. A first digit of 0 is never issued.

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