Luhn AlgorithmChecker
Validate credit card numbers using the Luhn algorithm (modulus 10 check). Fast, secure, and educational validation tool.
Enter Card Number to Validate
What is the Luhn Algorithm?
Learn about this essential validation method used by millions of systems worldwide
Definition
The Luhn algorithm, also known as the "modulus 10" check, is a simple checksum formula used to validate various identification numbers including credit card numbers, IMEI numbers, and more.
Purpose
Designed to detect accidental errors in typing or transmission of numbers, the algorithm can catch most single-digit errors and adjacent digit transpositions.
History
Invented by IBM researcher Hans Peter Luhn in 1954, it became part of the ISO/IEC 7812-1 standard and is now used globally in financial systems.
How It Works
Start from the rightmost digit and move left
Double every second digit from the right
If doubling results in a number > 9, subtract 9
Sum all digits together
If sum is divisible by 10, the number is valid
Key Features
Why our Luhn Algorithm Checker stands out from the rest
Secure Validation
All validation is performed locally on the client side, no sensitive data is transmitted to the server
Instant Results
Millisecond response time, real-time feedback on validation results, improving user experience
Step-by-Step Explanation
Provides detailed algorithm execution steps to help understand how the Luhn algorithm works
High Accuracy
Standard Luhn algorithm implementation, compliant with ISO/IEC 7812-1 international standard
Frequently AskedQuestions
Everything you need to know about the Luhn Algorithm
What is the Luhn algorithm?
How does the Luhn algorithm work?
Why validate credit card numbers?
Can Luhn validation guarantee the card number actually exists?
Which card numbers don't use the Luhn algorithm?
How to integrate Luhn validation in development?
Important Disclaimers
Educational Purpose: This tool is designed for educational and development purposes only.
Security Notice: Never use real credit card numbers for testing. Use only designated test numbers.
Validation Limitation: Luhn validation only checks mathematical correctness, not actual card existence or validity.
No Data Storage: All validations are performed locally in your browser. No data is sent to our servers.