A Philippine SSS number is the 10-digit identifier the Social Security System assigns to every member. It is normally written in a 2-7-1 grouping — a two-digit branch prefix, a seven-digit member serial, and a single trailing check digit. Before storing an SSS number in an HR or payroll system, or during PhilSys identity onboarding, you can confirm it is well-formed using the published Luhn check. This free validator runs that check entirely in your browser.
How it works
The validation has two parts:
- Format — strip dashes and spaces; the number must be exactly 10 digits.
- Luhn (mod-10) check — treat the final digit as a check digit over all ten:
- Working from the rightmost digit, double every second digit.
- If a doubled value exceeds 9, subtract 9.
- Sum every resulting digit.
- The number passes if the total is divisible by 10.
The tool also splits the number into its branch prefix, member serial and check digit so you can sanity-check each field.
Example
For an SSS number ending in a check digit that makes the Luhn total land on a multiple of 10, the result is valid. If a single digit is mistyped or transposed, the Luhn total will usually fall off the multiple of 10 and the number is flagged invalid — exactly the typo-catching behaviour a check digit is designed for.
A valid result confirms the number is well-formed, not that it is registered or active. Confirm membership through the official SSS channels. Everything here runs locally — your SSS number never leaves your device.