Fake Credit Card Number Generator

MockPayCard produces card numbers that look structurally real — correct length, correct issuer prefix, correct check digit — so developers and QA testers can exercise payment forms, checkout flows and validation logic without touching real financial data.

Typical use is filling a card field in a staging environment, feeding fixtures into an automated test suite, or verifying that your Luhn check and network-detection code behave correctly across Visa, Mastercard, Amex, Discover, Diners Club and JCB.

These numbers cannot be used for real purchases. They are not issued by any bank and are not connected to any account, balance or line of credit. Any live payment processor will decline them.

Card numbers carry a built-in error check called the Luhn algorithm. Starting from the rightmost digit and moving left, every second digit is doubled; if doubling produces a number above nine, nine is subtracted from it. All digits are then summed, and a valid number is one whose total is divisible by ten.

The final digit exists purely to make that sum come out right. This tool builds a number from a network prefix plus random digits, then computes the one check digit that completes the number, which is why every result passes a Luhn check on the first try.

The leading digits are the Issuer Identification Number (IIN), also called the BIN. The first six to eight digits identify the issuing institution and the network: Visa starts with 4, Mastercard with 51–55 or 2221–2720, American Express with 34 or 37, Discover with 6011 or 65, Diners Club with 300–305, 36 or 38, and JCB with 3528–3589. Length varies too — Amex is 15 digits, Diners Club 14, most others 16.