MAC Address Generator

Generate random, vendor-prefixed, or bulk MAC addresses. Validate existing MACs. Supports colon, hyphen, and Cisco dot notation.

Last reviewed: June 2026
Reviewed by , software engineer · last updated June 2026

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Generated MAC Address(es)
Click Generate to create a MAC address.

How the MAC Address Generator works

This tool generates, formats, and validates MAC addresses in local JavaScript. Random mode fills six octets with browser-side randomness, vendor mode fixes the first three octets to a selected OUI-style prefix, bulk mode repeats the generator, and validate mode normalizes colon, hyphen, and Cisco dot notation before checking the 48-bit structure.

The Locally Administered Address flag and multicast flag are bit-level controls on the first octet. Setting the LAA bit is useful for virtual machines, containers, lab devices, and privacy-oriented randomization. Setting the multicast bit creates an address for group delivery testing and is not appropriate for a normal unicast host address.

Workflow notes

  • Use generated values for labs: do not assign random MAC addresses on a production LAN without checking for conflicts.
  • Choose notation for the target system: Linux and macOS commonly use colon notation, Windows often displays hyphens, and Cisco tools often use dotted notation.
  • Understand OUI limits: a vendor prefix makes an address look familiar, but it does not prove the physical vendor of a device.
  • Validate pasted values: validation catches malformed hex, wrong group counts, and unsupported separators before you paste into a config.

Worked example

For a virtualization lab, enable the LAA flag and generate a bulk list in colon notation. The first octet should have the local bit set, which avoids pretending the address came from a globally assigned hardware block. Keep a record of assigned values so two virtual NICs do not collide on the same segment.

Sources

Frequently Asked Questions

A MAC (Media Access Control) address is a 48-bit hardware identifier assigned to a network interface controller (NIC). It is represented as 6 pairs of hexadecimal digits (e.g., AA:BB:CC:DD:EE:FF) and is used at the data-link layer of the OSI model to uniquely identify devices on a local network segment. The first 3 bytes (OUI) identify the vendor, and the last 3 bytes are assigned by the manufacturer.
The OUI (Organizationally Unique Identifier) is the first 3 bytes (24 bits) of a MAC address. It is assigned by the IEEE to hardware manufacturers and uniquely identifies the vendor. For example, Apple's OUI block includes prefixes like 00:17:F2, Intel uses prefixes like 00:1B:21, and Cisco uses prefixes like 00:1A:2B. Knowing the OUI lets network administrators identify which vendor manufactured a device.
A locally administered address (LAA) is a MAC address where bit 1 of the first octet is set to 1. This indicates the address was manually configured rather than burned in by the hardware manufacturer. LAAs are commonly used in virtualization (virtual machines, containers) and MAC randomization for privacy. In contrast, a globally administered address (GAA) has bit 1 set to 0 and was assigned by the IEEE via a hardware manufacturer.
Unicast MAC addresses (bit 0 of the first octet = 0) are intended for a single recipient. Multicast MAC addresses (bit 0 of the first octet = 1) are intended for a group of recipients. The broadcast address FF:FF:FF:FF:FF:FF is a special multicast address that reaches all devices on a segment. Network hardware uses the multicast bit to decide whether to pass a frame to the CPU or handle it in firmware.
There are three common notations: Colon-separated (AA:BB:CC:DD:EE:FF) - used by Linux, macOS, and most Unix tools; Hyphen-separated (AA-BB-CC-DD-EE-FF) - used by Windows and common in documentation; Dot-separated (AABB.CCDD.EEFF) - used by Cisco IOS, grouping octets in pairs. All three represent the same 48-bit value; the choice is purely a display convention.

Address notation checklist

MAC address display formats
FormatExampleCommon use
Colon-separated02:1A:2B:3C:4D:5ELinux, macOS, network documentation
Hyphen-separated02-1A-2B-3C-4D-5EWindows tools and exports
Cisco dotted021A.2B3C.4D5ECisco IOS and some switch outputs
LAA unicast02:00:00:00:00:01Virtual NICs and lab-generated addresses

Example walk-through

Generating lab addresses

Choose Random, keep colon notation, enable the locally administered bit, and set bulk count to the number of virtual NICs you need. Copy the generated list into your lab notes before assigning values.

To verify a pasted address, switch to Validate mode and enter a colon, hyphen, or dotted value. The tool reports whether the input has six valid octets and whether it is local/global and unicast/multicast.