🔢 Luhn Algorithm Validator

What Can the Luhn Algorithm Validator Do?

This is a free online Luhn algorithm (mod 10) validation tool that runs entirely in your browser. You can validate credit card numbers, IMEI numbers, ISBNs, and other Luhn-protected numbers, generate check digits, and batch validate multiple numbers. No data is ever uploaded to a server.

Core Features

• Number Validation: Check if credit card, IMEI, and other numbers have correct Luhn check digits
• Check Digit Generation: Enter digits without check digit, auto-calculate and append the correct one
• Batch Validation: Validate multiple numbers at once with CSV export
• Calculation Steps: Detailed display of each Luhn algorithm calculation step
• Card Type Detection: Auto-detect Visa, MasterCard, Amex, and other card types

How to Use

1. Select mode: Validate Number, Generate Check Digit, or Batch Validation
2. Enter the number in the input field, or click "Load Example" for a quick demo
3. The tool shows real-time validation results and calculation steps
4. Click "Copy Result" to save the validation output

Use Cases

Case 1: Developer Testing

When developing payment systems, validate test card numbers or generate Luhn-compliant test card numbers.

Case 2: Data Cleaning

Batch validate card numbers or IMEI numbers in a database to quickly filter out invalid entries.

Case 3: Security Auditing

Verify that stored identification numbers have correct format, ensuring data integrity.

Extended Knowledge

The Luhn algorithm was invented by IBM scientist Hans Peter Luhn in 1954. Steps: from right to left, double every second digit; if the product exceeds 9, subtract 9; sum all digits; if the total is divisible by 10, the number is valid. The algorithm detects all single-digit errors and most adjacent digit transpositions, but not certain specific double-digit swaps.

FAQ