Numbers & Finance · In-Browser Regular Expression Lab

Credit Card Regex — Validate Visa (13/16) and Mastercard (16) Numbers

Detects Visa and Mastercard credit card format with optional space or hyphen delimiters.

Pattern:

Regular Expression Pattern & Flags

Flags:

//none

Live Test String

Match Found

Load Sample:

Match Inspection & Details1 match

Match #1:4111111111111111

Test Samples Verification Matrix

Expected Valid Samples (Should Match)

4111111111111111 Pass

5500000000000004 Pass

2221000000000000 Pass

Expected Invalid Samples (Must Reject)

378282246310005 Rejected (Pass)

411111111111 Rejected (Pass)

9999999999999999 Rejected (Pass)

Code Implementation Generator

// JavaScript / TypeScript (ES6+)
const pattern = /^(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|2(?:22[1-9]|2[3-9][0-9]|[3-6][0-9]{2}|7[01][0-9]|720)[0-9]{12})$/;
const text = "4111111111111111";

const isMatch = pattern.test(text);
console.log("Is Match:", isMatch);

if (isMatch) {
  const matches = text.match(pattern);
  console.log("Matches:", matches);
}

Regular Expression Token Breakdown

Matches Visa starting with 4 (13 or 16 digits) and Mastercard starting with 51-55 or 2221-2720 (16 digits). Each component of the regular expression serves a distinct syntactical purpose as mapped below:

Token Pattern	Name / Component	Function & Rule
4[0-9]{12}(?:[0-9]{3})?	Visa Format	Starts with 4, total 13 or 16 digits.
5[1-5][0-9]{14}	Mastercard Legacy	Starts with 51-55, total 16 digits.
2[2-7]...[0-9]{12}	Mastercard 2-Series	Starts with 2221-2720, total 16 digits.

Frequently Asked Questions

Should I also run the Luhn algorithm?

Yes, regex validates prefix and length format, but Luhn checksum validation confirms mathematical validity.

Browse All 40 Patterns

Numbers & Finance

IBAN Bank Account Matcher

Validates canonical IBAN structure: 2-letter country code, 2-digit checksum, and up to 30 alphanumeric characters.

/^[A-Z]{2}[0-9]{2}[A-Z0-9]{4}[0-9]{7}([A-Z0-9]?){0,16}$/

Test regex

Numbers & Finance

US Phone Number Format

Flexible US phone number validator matching standard parentheses, hyphens, and spaces.

/^(?:\+?1\s*(?:[.-]\s*)?)?(?:\(\s*([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9])\s*\)|([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9]))\s*(?:[.-]\s*)?([2-9]1[02-9]|[2-9][02-9]1|[2-9][02-9]{2})\s*(?:[.-]\s*)?([0-9]{4})$/

Test regex

Code & Markup