Developer Tools
Credit Card Number Validator
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Validate credit card numbers using the Luhn algorithm. Identifies card type (Visa, Mastercard, Amex, etc.). No data leaves your browser.
Slik bruker du dette verktøyet
- Enter the card number you want to check.
- The Luhn checksum runs as you type and the card brand is detected from the prefix.
- Read whether the number passes the checksum and which network it belongs to.
Validates format only — does not verify if the card is active or has funds. Card number never stored or transmitted. No data leaves your browser.
Ofte stilte spørsmål
- What does the Luhn algorithm check?
- It is a checksum that catches single-digit typos and most transpositions. A number that passes is structurally valid but not necessarily a real, active card.
- Which card brands can it identify?
- It detects Visa, Mastercard, American Express, Discover, and other major networks from the number's leading digits.
- Does a passing number mean the card works?
- No. The Luhn check only verifies the math. It cannot tell you whether the account exists, has funds, or is active.
- Is the card number I enter transmitted or saved?
- No. The checksum and brand detection run in your browser, so the number is never sent to a server or written to storage.