Test Credit Card Numbers (Luhn Valid)
Generate valid Luhn check-digit credit card numbers for testing payment integrations — not real cards.
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Tags: test credit card numbers, fake card number generator, Luhn valid test card
Test Credit Card Numbers (Luhn Valid) Part of our complete guide to this topic — see the full series. Payment integration testing is one of the most common reasons developers need fake but valid-looking data. Submitting a randomly guessed 16-digit string to Stripe returns a card format error before even reaching the actual test. A Luhn-valid number with the right BIN prefix passes format validation and reaches the test processor's sandbox logic — where you can trigger specific responses by choosing the right test number. --- What is the luhn algorithm? The Luhn algorithm, developed by IBM engineer Hans Peter Luhn in 1954, is a simple checksum formula used to validate credit card numbers, IMEI numbers, and Canadian Social Insurance Numbers. It detects single-digit errors and transpositions…
Frequently Asked Questions
How do I generate test credit card numbers?
Start with a Bank Identification Number (BIN) prefix for the card network (4 for Visa, 51–55 for Mastercard, 34/37 for Amex). Fill the remaining digits randomly, then compute the Luhn check digit for the final position. The resulting number is Luhn-valid but not a real account number — it will be rejected by any real payment processor.
What Visa test card numbers work in Stripe?
Stripe's primary test Visa is 4242 4242 4242 4242 (any future expiry, any CVV). For a decline, use 4000 0000 0000 0002. For 3D Secure required, use 4000 0025 0000 3155. All Stripe test cards require test-mode API keys — they will not work in live mode.
How do I generate Luhn-valid card numbers?
The Luhn algorithm: sum digits right-to-left, doubling every second digit and subtracting 9 if doubled value > 9. If total % 10 == 0, the number is valid. To generate a valid number, fill all digits except the last, compute the total, then set the last digit to (10 - total % 10) % 10.
Are test card numbers safe to share?
Yes. Test card numbers generated with test BINs are Luhn-valid but not real account numbers. No bank will authorize a transaction on them. However, always use processor-specific test cards (Stripe's, PayPal's) in sandboxes rather than randomly generated numbers — random Luhn-valid cards may accidentally match a real card number's check digit.
What is the Stripe test card number?
Stripe's canonical success test card is 4242 4242 4242 4242 (Visa). Use any valid future expiration date (e.g., 12/34), any 3-digit CVC (e.g., 123), and any billing ZIP. This card works only in Stripe's test mode. In live mode, it will be rejected.
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