What is an example of a matching and non-matching string?

A valid matching string is "00:1A:2B:3C:4D:5E". A non-matching string is "00:1A:2B:3C:4D".

Is this regex safe from ReDoS (Catastrophic Backtracking)?

Yes, this pattern is optimized for linear execution time and safe for browser-side validation without locking up the UI thread.

HomeRegex LibraryHardware MAC Address Regex

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Hardware MAC Address Regex

Q: How do I test this regex in JavaScript and TypeScript?

Use regex.test(): const regex = /^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$/; const isValid = regex.test(inputString);

Matches standard 48-bit physical MAC addresses formatted with colons or hyphens.

Regular Expression Pattern:

/^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$/

Valid Match Example:

00:1A:2B:3C:4D:5E

Invalid / Non-Match Example:

00:1A:2B:3C:4D

Regex Syntax Breakdown & Explanation

•([0-9A-Fa-f]{2}[:-]){5} : First five pairs of hex digits followed by colon or dash
•([0-9A-Fa-f]{2}) : Final hex octet pair

Implementation in Popular Languages

JavaScript / TypeScript

const regex = /^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$/;
const isValid = regex.test("00:1A:2B:3C:4D:5E");
console.log(isValid); // true

Python (re)

import re

pattern = r"^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$"
match = re.match(pattern, "00:1A:2B:3C:4D:5E")
print(bool(match)) # True

Go (regexp)

package main
import (
  "fmt"
  "regexp"
)

func main() {
  re := regexp.MustCompile(`^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$`)
  fmt.Println(re.MatchString("00:1A:2B:3C:4D:5E"))
}

Frequently Asked Questions

Everything you need to know regarding specifications, syntax, and security best practices.

The regular expression pattern is /^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$/. Matches standard 48-bit physical MAC addresses formatted with colons or hyphens.