Run the Luhn mod 10 check on any number and see every doubled digit and the total
Runs in your browser. Nothing you type is sent anywhere. Checked against sources on 15 Oct 2026.The Luhn algorithm, also called mod 10, adds a number’s digits after doubling every second one from the right, and passes the number when the total ends in 0. Type any digits to see each step, the total and the check digit it should end in. Card numbers, IMEIs and many ID numbers use it. Nothing is sent anywhere, and a pass cannot pay for anything: it only catches typing mistakes.
| Digit | Doubled? | Counts as |
|---|---|---|
| 7 | No | 7 |
| 9 | Yes: 18 | 9 |
| 9 | No | 9 |
| 2 | Yes: 4 | 4 |
| 7 | No | 7 |
| 3 | Yes: 6 | 6 |
| 9 | No | 9 |
| 8 | Yes: 16 | 7 |
| 7 | No | 7 |
| 1 | Yes: 2 | 2 |
| 3 | No | 3 |
Write the number out and start from the rightmost digit, the check digit.
Moving left, double every second digit; take 9 off any result above 9.
Add all the digits, doubled and not, into one total.
The number passes when the total ends in 0; otherwise the page shows the last digit it needs.
Every payment gateway gives developers a sandbox: a test mode with its own keys, where a checkout can be tried end to end without moving money. Each gateway also publishes the card numbers its sandbox accepts. Stripe's best known is 4242 4242 4242 4242, a Visa that always succeeds; Razorpay lists domestic cards for India, including a RuPay card, 6527 6589 0000 1005.
This page hands out exactly those published numbers and nothing else. That is a deliberate rule. A "generator" that put random digits behind a real issuer prefix could produce the number of somebody's live card, and a gateway's sandbox would refuse it anyway, because test mode only knows its own list. So each number here is copied digit for digit from the gateway's page, with the source linked and the date it was read, and only the expiry date and CVV are made up: a month one to five years ahead, and three digits, or four for American Express, as Stripe asks.
The checker works on any number you paste. It runs the Luhn check, the mod 10 checksum in ISO/IEC 7812 that catches a mistyped digit and most swapped pairs, names the scheme from the first digits, and checks the length. It also says when a number is one of the published test cards. A pass means only that the number is well formed: whether a card exists, is active or has funds is known only to its bank.
The rest of the article, and all 6 questions about Test Credit Card Numbers, are on the Test Credit Card Numbers page.
Stripe's standard test card is 4242 4242 4242 4242, a Visa that always succeeds in test mode. Use any future expiry date and any three-digit CVC; American Express test cards take four digits. Stripe also publishes cards that decline, cards issued in countries such as India and the UAE, and cards that ask for 3D Secure.
Random digits behind a real issuer prefix can match the number of a real person's card, and gateways' sandboxes accept only their own published numbers anyway. Every number on this page is copied from Stripe's or Razorpay's test-card page, so it cannot belong to a live card and does work in test mode.
Paste the number into the checker. The Luhn check confirms the last digit fits the others, the first digits name the scheme, and the length is compared with what that scheme uses, such as 15 digits for American Express. A pass shows the number is well formed, not that the card exists or has funds.
Razorpay ka RuPay test card 6527 6589 0000 1005 hai. Yeh sirf Razorpay ke Test Mode mein chalta hai, live payment mein nahi. Koi bhi future expiry aur koi bhi CVV daaliye, phir test bank page par 4 se 10 digit ka OTP daaliye. Is number se kuch kharida nahi ja sakta.
Rates and rules change; check the source before you rely on a figure.
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