Are these real credit card numbers?

No. These numbers are mathematically valid per the Luhn algorithm but they are not linked to any bank account, issuer, or cardholder. They will pass format/checksum checks but will fail any real authorization attempt.

How does the Luhn algorithm work?

Starting from the second-to-last digit and moving left, double every second digit. If doubling produces a value greater than 9, subtract 9. Sum all digits including the undoubled ones. Append a check digit so that the total sum is divisible by 10.

What length should I use for credit card testing?

Most credit cards use 16 digits. Visa, Mastercard, and Discover use 16; American Express uses 15; Diners Club uses 14. Use the matching length for your test case.

Can I generate Visa or Mastercard test numbers specifically?

Yes — enter the IIN/BIN prefix in the "Fixed Prefix" field. Visa cards start with 4, Mastercard with 51–55, American Express with 34 or 37, Discover with 6011.

Is the Luhn check digit always the last digit?

Yes. The check digit is the final digit of the number. All preceding digits are the payload, and the last digit is chosen so the whole string passes the Luhn mod-10 test.

Can I use these numbers in production?

No. These are for testing and development purposes only. Using fake card numbers in a real payment context is fraud. Use your payment processor's official sandbox test numbers for integration testing.

Luhn Number Generator

Name: Luhn Number Generator
Availability: InStock
Author: Nham Vu

Generate Luhn-valid numbers of any length for testing credit card validators, account number systems, and check-digit implementations.

Generator Options

Total Length — 16 digits

819

Fixed Prefix (optional)

Digits only. Must be shorter than the total length.

Quantity — 10

1100

Quick Presets

Generated Numbers

No numbers generated yet

Configure options on the left and click Generate.

Luhn check digit calculation (step by step)

Generate a number above to see the step-by-step Luhn check digit calculation.

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Summary

Generate Luhn-valid numbers of any length for testing credit card validators, account number systems, and check-digit implementations.

How it works

Set the desired total digit length (8–19 digits).
Optionally enter a fixed prefix (e.g. "4" for Visa or "5" for Mastercard).
Choose how many numbers to generate (1–100).
Click "Generate" to produce a list of Luhn-valid numbers.
The tool fills random digits then calculates the correct Luhn check digit automatically.
Copy individual numbers or export the full list as plain text.

Use cases

Generate test credit card numbers for payment form validation.
Seed test databases with Luhn-valid account numbers.
Verify your own Luhn validation implementation against known-good inputs.
Create dummy IMEI codes for mobile device testing.
Test barcode or loyalty card scanners that check Luhn validity.
Understand how the Luhn algorithm constructs a check digit interactively.
Generate bulk test data for QA automation suites.
Prototype payment flows without using real card numbers.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu