How the pattern works
| Part | Meaning |
|---|---|
4\d{12}(?:\d{3})? | Visa: starts with 4, 13 or 16 digits |
5[1-5]\d{14} | Mastercard: 51–55, 16 digits |
3[47]\d{13} | American Express: 34 or 37, 15 digits |
Code examples
JavaScript
const re = /^(?:4\d{12}(?:\d{3})?|5[1-5]\d{14}|3[47]\d{13})$/;
re.test(value); // true or falsePython
import re
bool(re.fullmatch(r'(?:4\d{12}(?:\d{3})?|5[1-5]\d{14}|3[47]\d{13})', value))PHP
preg_match('/^(?:4\d{12}(?:\d{3})?|5[1-5]\d{14}|3[47]\d{13})$/', $value) === 1;Notes and limitations
Remove spaces and dashes before testing, then run a Luhn checksum — the regex only checks the shape. Mastercard also issues 2221–2720 numbers; add |2(?:2[2-9]|[3-6]\d|7[01]|720)\d{12} to cover them. Never log or store raw card numbers. The examples are standard test numbers.
Regex TesterType a pattern and watch matches highlight live in your test text.
Open the tool Frequently asked questions
What is the regex for credit card number?
/^(?:4\d{12}(?:\d{3})?|5[1-5]\d{14}|3[47]\d{13})$/ — it matches the whole string. See the table above for what each part does.
Which examples match?
Of the examples tested, these match: 4111111111111111, 5500000000000004, 378282246310005. The others don’t.
How do I test this regex?
Click “Open in Regex Tester” — the pattern, flags and sample text load automatically, and matches highlight as you edit.