Credit Card Validation
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Enter card number to detect
Test with Sample Cards:
Validation Results
❌
Validity
❌
Checksum
❌
Length
Detailed Analysis
Card Information
Card Type:
Unknown
Expected Length:
N/A
Starts With:
N/A
Industry:
N/A
Validation Details
Luhn Check:
❌ Failed
Length Check:
❌ Failed
Format Check:
❌ Failed
Overall Status:
❌ Invalid
How Luhn Algorithm Works
Step-by-Step Process:
- Start from the rightmost digit
- Double every second digit
- If doubled digit > 9, subtract 9
- Sum all digits
- If sum ends with 0, card is valid
Example: 4111 1111 1111 1111
Original: 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Doubled: 8 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1
Sum: 8+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1 = 40 ✓
Doubled: 8 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1
Sum: 8+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1 = 40 ✓
Credit Card Types
Visa
• Starts with 4
• Length: 13, 16, 19
• Most common worldwide
• Length: 13, 16, 19
• Most common worldwide
Mastercard
• Starts with 5[1-5] or 2[2-7]
• Length: 16
• Second most common
• Length: 16
• Second most common
American Express
• Starts with 34 or 37
• Length: 15
• Premium cards
• Length: 15
• Premium cards
Discover
• Starts with 6011, 622126-622925, 644-649, 65
• Length: 16, 19
• US-based network
• Length: 16, 19
• US-based network
Luhn Algorithm Steps
Important Security Notice
⚠️ This tool is for educational purposes only. Never enter real credit card numbers for validation.
🔒 Privacy: All validation happens locally in your browser. No data is sent to any server. No CVV, expiry, or cardholder name is requested or stored.
📚 Learning: Use this tool to understand how credit card validation algorithms work (Luhn + BIN/prefix length rules).
🚫 Legal: Do not use this tool for fraudulent activities or testing stolen card numbers.