The Social Insurance Number (SIN) is a nine-digit number that you need to work in Canada or to have access to government programs and benefits. A SIN is issued to one person only and it cannot legally be used by anyone else. You are responsible for protecting your SIN. Store any document containing your SIN and personal information in a safe place.
The SIN is formatted as three groups of three digits (123 456 789). (wikipedia)
Social Insurance Numbers can be validated through a simple check digit process called the Luhn algorithm.
From the rightmost digit, which is the check digit, and moving left, double the value of every second digit. If the result of this doubling operation is greater than 9, then add the digits of the product. Take the sum of all the digits. If the total mod 10 is equal to 0, then the number is valid, else it is not valid.
This tool was developed for programmers and testers who have the constant need to enter different SIN numbers in developing forms.