Calculator reference
Verification evidence and limitations →
What it calculates
Checks a ten-digit service-establishment number using the chosen check-digit method.
Inputs and methods
Ten decimal digits; select the documented AMEX method or the separate MOD 9 convention.
Worked example
Select MOD 9 and enter test value 7992739874.
Check passed
Specification and limits
The two methods are not interchangeable. A passing check digit does not establish merchant registration.
American Express merchant resources ↗