Canada SIN Validator
Online validator for Canadian Social Insurance Number (SIN / NAS) according to ESDC and CRA guidelines.
How does Canadian SIN validation work?
The validator checks that the string contains exactly 9 digits, verifies that the first digit represents a valid active Canadian region (1 to 7 or 9), and applies the Luhn checksum formula (Modulo 10).
If the weighted Luhn sum is an exact multiple of 10, the SIN is confirmed to be structurally and mathematically valid.
SIN Check Digit Calculation Algorithm
The 9th digit of the SIN is validated using the standard Luhn algorithm (Mod 10) applied to the first 8 digits:
Sum = Σ dᵢ × (if i even: 2, if i odd: 1) [with two-digit reduction]; Checksum = (10 - (Sum mod 10)) mod 10
- Check that the first digit is a valid regional prefix (1, 2, 3, 4, 5, 6, 7, or 9).
- Multiply the first 8 digits alternately by 1 and 2 from left to right (weights 1, 2, 1, 2, 1, 2, 1, 2).
- If any product is 10 or greater, add the individual digits of that product together (e.g. 8 × 2 = 16 → 1 + 6 = 7).
- Sum all resulting values together.
- The 9th check digit is the number required to round the sum up to the nearest multiple of 10.