Luhn Credit Card Validator
A free online credit card validator using the Luhn Mod 10 checksum algorithm. Instantly identify credit card networks (Visa, Mastercard, Amex, Discover, Diners Club, JCB, UnionPay) based on IIN prefix standards. Check sequence lengths and explore a visual, step-by-step mathematical grid showing doubling, summing digits, and modulo congruent checks. All calculations run client-side for maximum security.
Card Input & Detection
Formats: digits only. All spaces and hyphens are stripped automatically.
• Luhn mod 10 checksum: Failed
• Length match (11): Wrong length for identified brand
• Network: Visa
- Visa: 4xxx
- Mastercard: 51-55 / 22-27
- Amex: 34 / 37
- Discover: 6011 / 65
- Diners: 36 / 300-305
- JCB: 3528-3589
Interactive Luhn Math Breakdown
| Digits (L➔R) | #1 | #2 | #3 | #4 | #5 | #6 | #7 | #8 | #9 | #10 | #11 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Card Digit | 4 | 9 | 9 | 2 | 7 | 3 | 9 | 8 | 7 | 1 | 6 |
| Multiplier | ×1 | ×2 | ×1 | ×2 | ×1 | ×2 | ×1 | ×2 | ×1 | ×2 | ×1 |
| Subtotal | 4 | 18 | 9 | 4 | 7 | 6 | 9 | 16 | 7 | 2 | 6 |
| Adjusted Sum | 4 | 9 | 9 | 4 | 7 | 6 | 9 | 7 | 7 | 2 | 6 |
Final Equation Verification
4 + 9 + 9 + 4 + 7 + 6 + 9 + 7 + 7 + 2 + 6 = 70
✓ Valid: The final sum matches exactly congruent to 0 Modulo 10. The number has a valid structure!
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