Credit Card Test Number Generator

About Credit card test number generator

Generates card-like numbers that pass the Luhn checksum and follow real issuer prefixes, so forms and payment sandboxes can be tested without touching a genuine card. It also has a validator that tells you why a number fails. These are test numbers only: not issued cards and never usable for purchases.

How to use it

1. Leave Mode on Generate and choose a Brand: Visa, Mastercard, American Express, Discover, JCB or Diners Club.
2. Set How many, from 1 to 500. Changing the brand regenerates the list at once.
3. Switch Format with spaces on or off to match the field you are testing.
4. Select Generate, then Copy all or Download CSV. Each row also has its own random expiry and CVV.
5. Switch Mode to Validate and type any number to see its brand, length and the reason it fails.

Validating a number with one wrong digit

Validate: 4111 1111 1111 1112

Not valid, Visa, 16 digits. Fails the Luhn checksum; the last digit should be 1. Changing the last digit to 1 turns the badge to Luhn-valid.

When to use it

• Testing that a checkout form accepts a correct card format and rejects a mistyped one.
• Loading a QA database with hundreds of sample card numbers that look realistic.
• Exercising client-side card validation code for each brand's length and grouping rules.
• Learning how the Luhn algorithm reports a single wrong digit.

Questions about Credit card test number generator

Will a sandbox payment gateway accept these numbers?

Not necessarily. Many gateways only approve the specific test numbers in their own documentation. These pass format checks and Luhn validation, but a sandbox may still decline them.

What is the Luhn check?

Working from the right, every second digit is doubled, with 9 subtracted when the result exceeds 9, and the total must be a multiple of ten. It catches most single-digit typos and swaps of neighboring digits.

Why does American Express look different?

Amex numbers are 15 digits grouped 4-6-5 and start with 34 or 37, and the security code has four digits. The other brands here use 16 digits with a three-digit code, except Diners Club at 14.

Does a passing result mean the card exists?

No. The validator only confirms the checksum, a recognized prefix and a plausible length. Never enter a real card number in this page.

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