Mac Address Generator

Generate valid MAC addresses for virtual machines, containers, lab networks and test data. Choose locally administered or a vendor prefix (OUI), unicast or multicast, the output format and how many you need — then copy or download the list.

What a MAC address is

A MAC (media access control) address is the 48-bit hardware address used by Ethernet, Wi-Fi and many other networks to deliver frames to the right interface on a local network. It is written as six bytes in hexadecimal, such as 00:1A:2B:3C:4D:5E. Physical network cards ship with a globally unique address assigned by the manufacturer, but virtual machines, containers, test labs and network simulations need addresses too — which is what this generator creates.

How MAC addresses are structured

In practice, you can tell a locally administered unicast address by the second hex digit: it is 2, 6, A or E (as in 02:…, x6:…, xA:…, xE:…). Multicast addresses have an odd first byte.

Which type should I generate?

• Locally administered unicast is the safe default for virtual machines, containers, lab equipment and test data. These addresses are reserved for local assignment and will never collide with a manufacturer's universally assigned address.
• Vendor prefix (OUI) is used when software expects a specific vendor range — for example, some hypervisors use their own prefix for virtual NICs. Only use a vendor prefix you are entitled to use, or one your platform documents for this purpose.
• Fully random unicast creates addresses in the universally administered space; they may coincide with real hardware, so avoid them on live networks.
• Multicast addresses identify groups, not single interfaces; generate them only for protocol testing.

Output formats

Different systems write MAC addresses differently. Linux and macOS use lowercase colon-separated bytes (00:1a:2b:3c:4d:5e); Windows commonly shows uppercase hyphens (00-1A-2B-3C-4D-5E); Cisco devices use three groups of four hex digits separated by dots (001a.2b3c.4d5e); some databases and APIs store the 12 digits without separators. Choose the format your configuration file or tool expects to avoid conversion errors.

Worked example

You need ten addresses for virtual machines in a home lab. Choose “Locally administered, unicast”, set the count to 10 and the format to colons. Each address starts with a byte whose second hex digit is 2, 6, A or E — for example 5a:3f:91:0c:7e:22 — so they are marked as locally administered and unicast. Copy the list into your VM configuration, one per machine. The checker confirms any address's type: 02:42:ac:11:00:02, a typical container address, is valid, unicast and locally administered.

Uniqueness and randomness

The generator uses your browser's cryptographic random number generator and removes duplicates within a batch. With 46 random bits in a locally administered unicast address, the chance of two random addresses matching in a small network is extremely low, but not zero; for large deployments, keep a register of assigned addresses or use your platform's address management. The tool runs entirely in your browser and does not store or send the addresses anywhere.

MAC randomisation on phones and laptops

Modern operating systems often use randomised, locally administered MAC addresses when scanning for or joining Wi-Fi networks, to make devices harder to track. That is why you may see addresses on your router with a second hex digit of 2, 6, A or E instead of the vendor's prefix. If you use MAC filtering or DHCP reservations, you may need to turn off randomisation for that network on the device, or reserve the randomised address.

Common uses in testing and development

Developers use generated MAC addresses to seed test databases for network inventory tools, to exercise input validation in forms and APIs, to create realistic fixtures for DHCP or RADIUS testing, and to assign stable addresses to lab virtual machines so that DHCP reservations and firewall rules do not change between rebuilds. For fixtures, keep the generated list with the test data so results are reproducible, and prefer locally administered addresses so there is no chance of accidentally matching a real device on a shared network.