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.

What does the first digit of a SIN mean?

It indicates where the SIN was registered. 1 covers the Atlantic provinces, 2–3 is Quebec, 4–5 is Ontario, 6 covers the Prairies and territories, 7 is BC and Yukon, 9 is a temporary resident, and 0 is never issued.

Why do SINs starting with 9 get flagged differently?

A 9 prefix is reserved for temporary residents and the SIN usually has an expiry date. It still must pass the Luhn check, but it signals a non-permanent number rather than a citizen or permanent-resident SIN.

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)

A Canadian Social Insurance Number (SIN) is the 9-digit identifier issued for work and government services, usually written as AAA-BBB-CCC. This validator confirms a SIN is mathematically well-formed using the official Luhn (mod-10) check digit, and reads the registration region from the first digit. It is built for developers testing forms and anyone checking a number for typos — and it never contacts any government system.

How it works

The validator strips out spaces and dashes, then requires exactly 9 digits. It applies the Luhn algorithm: working left to right, every second digit (positions 2, 4, 6, 8) is doubled, and any result above 9 has 9 subtracted. All nine resulting digits are summed, and the SIN is valid only if that total is divisible by 10. The first digit is then matched to a province or category. A leading 0 is never issued, so it is treated as invalid even if the math works.

First digit	Region
1	NB / NL / NS / PEI
2–3	Quebec
4–5	Ontario
6	MB / SK / AB / Territories
7	BC / Yukon
9	Temporary resident
0	Invalid — never issued

Example

Take the SIN 130 692 544. Doubling every second digit and subtracting 9 where needed gives a digit sum of 40, which is divisible by 10, so the Luhn check passes — and the leading 1 maps to the Atlantic provinces, so it is reported as well-formed. By contrast, a number with a leading 0 is rejected outright because that prefix is never issued.

A passing check confirms the number’s structure only — not that it was ever issued. The Luhn check runs entirely in your browser; nothing is uploaded.