How to use the Credit Card Formatter
Format and mask card numbers in seconds with no configuration needed.
1
Enter the card number
Type or paste a raw card number (digits only, with or without spaces) into the input field. The tool automatically detects the card network as you type.
2
Choose display options
Select whether to show the full formatted number or mask the middle digits (e.g., 4111 **** **** 1111). Toggle the network badge to confirm the detected card type.
3
Copy the formatted number
Click "Copy" to copy the formatted or masked number to your clipboard and use it in your UI, documentation, or test suite.
When to use this tool
Use the Credit Card Formatter when you need to display, document, or test card numbers in the correct visual format.
- →Formatting test card numbers for payment gateway documentation or internal wikis
- →Masking real card numbers (e.g., **** **** **** 4242) for UI mockups or screenshots
- →Verifying the correct group spacing for a specific card network during UI development
- →Generating correctly formatted sample card numbers for QA test cases
- →Displaying partial card numbers securely in customer-facing receipts or confirmation emails
- →Checking whether a raw card number string matches the expected format for a given network
Frequently asked questions
Q:Which card networks does the formatter support?
The tool supports all major card networks including Visa (16 digits, groups of 4), Mastercard (16 digits, groups of 4), American Express (15 digits, 4-6-5 grouping), Discover (16 digits, groups of 4), Diners Club, JCB, and UnionPay.
Q:How does the tool detect the card network automatically?
Card network detection is based on the IIN (Issuer Identification Number) — the first 1–6 digits of the card number. For example, Visa cards always start with 4, and Amex cards start with 34 or 37.
Q:Is it safe to enter real credit card numbers here?
While all processing happens in your browser with no server transmission, we strongly recommend only using test card numbers (such as those provided by Stripe or PayPal) in any online tool. Never enter real, live credit card numbers into third-party web tools.
Q:What does "masking" a credit card number mean?
Masking replaces sensitive middle digits with asterisks or bullet characters, leaving only the first 4 and last 4 digits visible (e.g., 4111 **** **** 1111). This is the standard display format used in receipts, account pages, and customer emails.
Q:Why does American Express use a different format from other cards?
Amex cards are 15 digits long and use a 4-6-5 grouping (e.g., 3714 496353 98431) rather than the standard 4-4-4-4 grouping. This is a deliberate network design choice by American Express that dates back to the original card issuance system.
Q:Can I use this tool to validate a Luhn checksum?
Yes, the formatter runs a Luhn algorithm check on the entered number and indicates whether the number passes basic validation. Note that passing the Luhn check only means the number is structurally plausible — it does not mean the card is real or active.