Credit Card Validator
Free online credit card validator using the Luhn algorithm. Validate credit card numbers instantly, detect card types, and verify format securely in your browser.
Instant Validation
Real-time Luhn algorithm check
100% Secure
Client-side only, no data sent
Card Type Detection
Auto-detect Visa, Mastercard, Amex
Enter card number with or without spaces/dashes
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How to Validate Credit Card Numbers
Enter Card Number
Type or paste your credit card number into the validator. Spaces and dashes are automatically removed.
Automatic Validation
The validator checks the number using the Luhn algorithm in real-time as you type.
View Results
See validation status, card type, length, and Luhn algorithm check result instantly.
Verify Format
Confirm the credit card number follows the correct format and passes all validation checks.
Why Use Our Credit Card Validator?
Development & Testing
Validate credit card numbers during application development, test payment forms, and verify card number input validation logic.
Form Validation
Check credit card number format before form submission, improve user experience with instant feedback, and reduce payment processing errors.
Education & Learning
Understand how the Luhn algorithm works, learn about credit card number formats, and study payment card industry standards.
Quick Verification
Quickly verify credit card number format, check if numbers are correctly formatted, and validate card type detection logic.
Frequently Asked Questions
Our credit card validator uses the Luhn algorithm (also known as the modulus 10 algorithm) to verify credit card numbers. This mathematical formula checks if a credit card number is valid by validating the checksum digit. The validator also identifies the card type (Visa, Mastercard, American Express, etc.) based on the card number prefix.
Yes, absolutely. All validation happens entirely in your browser using client-side JavaScript. Your credit card number never leaves your device, is never sent to any server, and is never stored or logged. This ensures complete privacy and security.
The validator supports all major credit card types including Visa, Mastercard, American Express, Discover, Diners Club, JCB, and UnionPay. It automatically detects the card type based on the card number prefix and validates the number format accordingly.
Yes, the validator works with debit cards that use the same numbering system as credit cards. Most debit cards follow the same Luhn algorithm validation rules, so you can validate debit card numbers using this tool.
The Luhn algorithm is a simple checksum formula used to validate identification numbers, including credit card numbers. It works by checking the last digit (checksum) against the rest of the number. If the checksum matches the calculated value, the number is considered valid according to the Luhn algorithm.
No, a valid Luhn check only means the number follows the correct mathematical formula. It does not verify if the card actually exists, is active, has available credit, or belongs to you. The Luhn algorithm is just a format validation, not an authorization check.
Key Features
Instant Validation
Real-time credit card number validation using the Luhn algorithm. Get immediate feedback as you type.
Card Type Detection
Automatically identifies card type including Visa, Mastercard, American Express, Discover, and more.
100% Client-Side
All validation happens in your browser. Your card numbers never leave your device - complete privacy guaranteed.
Luhn Algorithm
Uses the industry-standard Luhn algorithm (modulus 10) to verify credit card number checksums.
Format Validation
Validates card number length, format, and structure according to payment card industry standards.
Free Unlimited Use
Completely free with no limits, registration, or hidden fees. Validate as many card numbers as you need.
Credit Card Validator - Free Online Luhn Algorithm Checker
Our free online credit card validator uses the Luhn algorithm (also known as the modulus 10 algorithm) to instantly validate credit card numbers. This powerful tool helps developers, testers, and users verify credit card number formats, detect card types, and ensure proper input validation. All validation happens entirely in your browser using client-side JavaScript, ensuring your sensitive card numbers never leave your device.
How Credit Card Validation Works
Credit card validation using the Luhn algorithm is a mathematical checksum method that verifies the integrity of credit card numbers. The algorithm works by checking the last digit (checksum) of the card number against a calculated value based on the preceding digits. When you enter a credit card number into our validator, it automatically removes spaces and dashes, then applies the Luhn algorithm to determine if the number is mathematically valid. The validator also identifies the card type based on the card number prefix - Visa cards start with 4, Mastercard with 5, American Express with 34 or 37, and so on.
Understanding the Luhn Algorithm
The Luhn algorithm, developed by IBM scientist Hans Peter Luhn in 1954, is a simple checksum formula used to validate identification numbers. For credit cards, the algorithm works by:
- Starting from the rightmost digit (excluding the check digit), double every second digit
- If doubling results in a two-digit number, add the digits together
- Sum all the digits in the card number
- If the total is divisible by 10, the card number is valid according to the Luhn algorithm
This mathematical validation ensures that credit card numbers follow a specific pattern, making it easier to detect common input errors like transposed digits or missing numbers. However, it's important to note that a valid Luhn check only confirms the number follows the correct format - it doesn't verify if the card actually exists or is active.
Supported Credit Card Types
Our credit card validator supports all major card types including Visa, Mastercard, American Express, Discover, Diners Club, JCB, and UnionPay. Each card type has specific characteristics:
- Visa: 13 or 16 digits, starts with 4
- Mastercard: 16 digits, starts with 51-55 or 2221-2720
- American Express: 15 digits, starts with 34 or 37
- Discover: 16 digits, starts with 6011, 65, or 644-649
- Diners Club: 14 digits, starts with 300-305, 36, or 38
- JCB: 16 digits, starts with 3528-3589
- UnionPay: 16-19 digits, starts with 62
Security and Privacy Features
One of the key advantages of our credit card validator is complete client-side processing. All validation happens entirely in your browser using JavaScript - no data is sent to any server, stored in databases, or logged anywhere. This means your credit card numbers remain completely private and secure. Whether you're testing payment forms, validating card number inputs, or learning about credit card formats, you can use this tool with confidence knowing your sensitive information never leaves your device.
Use Cases for Credit Card Validation
Developers use credit card validators during application development to test payment forms, verify input validation logic, and ensure proper card number formatting. E-commerce websites implement Luhn algorithm checks to provide instant feedback to users entering card numbers, improving user experience and reducing payment processing errors. Testers use validators to verify that applications correctly handle valid and invalid card numbers. Students and educators use these tools to understand payment card industry standards and learn how credit card validation algorithms work.
Free Online Credit Card Validator Tool
Swapcode's credit card validator is completely free with unlimited use and no registration required. Unlike other validators that may send your data to servers, our tool runs entirely in your browser, ensuring maximum privacy and security. The validator provides instant feedback, automatically detects card types, and validates numbers using the industry-standard Luhn algorithm. Whether you're a developer building payment forms, a tester verifying application functionality, or someone learning about credit card validation, our free online credit card validator is the perfect tool for validating card numbers securely and instantly.
Ready to Validate Credit Card Numbers?
Start validating credit card numbers instantly with our free, secure, client-side credit card validator. No registration required.
Validate Credit Card Now