💳 Credit Card Validator
Validate credit card numbers, detect card networks, and mask numbers for safe display. All processing runs in your browser — nothing is sent to any server.
🧪 Test Card Numbers
| Network | Starts With | Length |
|---|---|---|
| Visa | 4 | 13, 16, 19 |
| Mastercard | 51-55, 2221-2720 | 16 |
| Amex | 34, 37 | 15 |
| Discover | 6011, 644-649, 65 | 16-19 |
| JCB | 3528-3589 | 16-19 |
| Diners Club | 300-305, 36, 38 | 14-19 |
| UnionPay | 62 | 16-19 |
What Is the Luhn Algorithm?
The Luhn algorithm (also called the Modulus 10 algorithm) is a simple checksum formula used to validate identification numbers such as credit card numbers, IMEI numbers, and Canadian Social Insurance Numbers. It was created by IBM scientist Hans Peter Luhn in 1954.
The algorithm works by:
- Starting from the rightmost digit, double every second digit.
- If doubling results in a number greater than 9, subtract 9.
- Sum all the digits.
- If the total modulo 10 is 0, the number is valid.
How to Use This Tool
- Enter a credit card number in the input field.
- Click Validate to check the number.
- View the detected card network, Luhn check result, and masked number.
- Try the test card numbers to see different networks detected.
Why Use This Tool?
- Validate card numbers using the industry-standard Luhn algorithm.
- Detect card networks (Visa, Mastercard, Amex, etc.) from the BIN/IIN.
- Generate masked card numbers for safe display in UIs.
- 100% client-side — your card number is never sent anywhere.
Frequently Asked Questions
Is it safe to enter my real card number?
This tool runs entirely in your browser. Your card number is never transmitted over the network or stored anywhere. However, for testing purposes, we recommend using the publicly available test card numbers provided above.
Can this tool charge my card?
Absolutely not. This tool only performs mathematical validation (Luhn check) and pattern matching. It has no payment processing capability whatsoever.
Why does my valid card show as invalid?
Some prepaid, virtual, or regional card numbers may not match the standard BIN patterns. The Luhn check is still performed correctly — if it passes, the number is mathematically valid.