Credit Card Validator Online – Check Card Numbers and Detect the Network
Credit Card Validator
Use this free credit card validator online to check if a credit or debit card number is valid with the Luhn algorithm. Perfect for developers and testing.
Quick answer
To use this credit card validator online, type or paste a card number into Enter Card Number. As you type, the number is grouped like a real card, the network logo updates on the card preview and the tool runs the Luhn checksum. You will see Valid Card Number or Invalid Card Number, plus the card network (Visa, Mastercard, American Express, Discover, JCB, Diners Club, UnionPay or Maestro) and the industry from the first digit. Nothing is sent to a server.
Developers, testers and support teams often need to know whether a card number is at least correctly formed before it reaches a payment gateway. This free credit card validator online answers that in real time with the Luhn check, network detection from the card prefix and a visual card preview.
I added UnionPay and Maestro detection to the existing networks, so numbers starting with 62 or common Maestro prefixes are no longer shown as unknown. The validator is for checking format only; it never charges or contacts a card.
Credit Card Validator Online Features
| Feature | How it works |
|---|---|
| Real-time Luhn check | Validates as you type, with no button to press |
| Network detection | Visa, Mastercard, Amex, Discover, JCB, Diners Club, UnionPay and Maestro |
| Card preview | Shows the number and network on a virtual card |
| Smart formatting | Groups digits like a real card, including the 4-6-5 Amex layout |
| Industry (MII) | Shows the industry from the first digit, such as banking or travel |
| Clear results | Valid or invalid with a short explanation |
| Developer friendly | Great for checking test card numbers and form validation |
| Private | Runs locally; card numbers are never transmitted or stored |
How to Use the Credit Card Validator Online
Step 1: Type or paste the card number
Click Enter Card Number and type or paste the digits. Spaces are added automatically in the right places, so you can compare the number with the card or your test data easily.
Step 2: Check the network shown on the card preview
The virtual card updates as you type, showing the detected network, such as Visa, Mastercard or American Express. The network comes from the first digits of the card number, called the IIN or BIN.
Step 3: Read the validity result and card details
Once the number is long enough, the result box shows Valid Card Number or Invalid Card Number. It also lists the card network and the industry identified by the first digit. An invalid result usually means a typo.
How Card Numbers Are Built
- First digit (MII): the industry, for example 4 and 5 for banking and finance, 3 for travel and entertainment.
- First 6 to 8 digits (IIN/BIN): identify the card network and the issuing bank.
- Middle digits: the individual account number.
- Last digit: the Luhn check digit that makes the whole number pass the Mod 10 test.
Card Number Prefixes by Network
- Visa: starts with 4, usually 16 digits.
- Mastercard: starts with 51 to 55 or 2221 to 2720, 16 digits.
- American Express: starts with 34 or 37, 15 digits.
- Discover: starts with 6011 or 65, 16 digits.
- JCB: starts with 35, 16 digits.
- UnionPay: starts with 62, 16 to 19 digits.
What a Credit Card Validator Can and Cannot Do
This credit card validator online confirms that a number is correctly formed and identifies its network. It cannot tell whether the card exists, is active, has funds or belongs to a particular person, because that information is only available to the issuing bank. For testing checkouts, use the official sandbox numbers from Stripe, PayPal or your payment provider instead of real cards.
Frequently Asked Questions
Is this credit card validator online free?
Yes. It is free with no sign-up and no limits.
Is it safe to enter a card number here?
The check runs entirely in your browser and nothing is sent or saved. Still, for testing it is best to use published test card numbers rather than a real card.
Does a valid result mean the card can be charged?
No. It only means the number passes the Luhn check and matches a known network pattern. Only the issuing bank can confirm the card is real and active.
Which card networks are detected?
Visa, Mastercard, American Express, Discover, JCB, Diners Club, UnionPay and Maestro.
Why is my number invalid?
The most common reasons are a mistyped or missing digit, or two digits swapped. Check the number against the card and try again.
Can I check the CVV or expiry date?
No. CVV and expiry dates are not part of the card number and can only be verified by the card issuer during a real payment.