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MAC Address Generator

Generate random MAC addresses for virtual machines, containers, and tests. The MAC address generator sets the locally administered bit by default, so the addresses can't clash with real hardware.

Generated in your browser with a cryptographic random source.
Built by · Updated
Letters

The first 3 bytes (OUI). When set, they are used as typed and the two checkboxes above are ignored.

MAC addresses

    How to use the MAC Address Generator

    1. Set How many, pick a Format, and choose uppercase or lowercase Letters.
    2. Keep Locally administered (LAA) ticked for VMs and tests, or type a Vendor prefix if a system only accepts one maker's addresses.
    3. Press Generate, then copy one address, copy all, or download the list.

    How it works

    A MAC address is 6 bytes (48 bits). Two bits of the first byte have a fixed meaning:

    • Bit 0 (I/G): 0 = unicast, one device. 1 = multicast, a group.
    • Bit 1 (U/L): 0 = universally administered, burned in by the maker under its OUI. 1 = locally administered, set by software.

    The generator draws 6 random bytes from your browser's cryptographic source, then sets those two bits from your options. A locally administered unicast address always has 2, 6, A, or E as its second hex digit, as in x2:, x6:, xA:, or xE:. With a vendor prefix, the first 3 bytes are used exactly as typed and only the last 3 are random.

    Examples

    • Colon format, locally administered: 02:4F:9A:1C:77:E3.
    • Hyphen format, as Windows shows it: 06-B1-2C-8E-40-5D.
    • Cisco format, lowercase: 0ae3.5b71.c209.
    • With vendor prefix 52:54:00 (QEMU/KVM): 52:54:00:3D:A0:19.

    Limitations

    • Random addresses can repeat. With 46 random bits the chance is tiny, but check for duplicates in very large lists.
    • A real vendor prefix can clash with that vendor's hardware on the same network. Use one only in labs or where a system requires it.
    • Multicast addresses can't be assigned to a network card as its own address. Tick Multicast only to create group addresses.

    Frequently asked questions

    What is a locally administered MAC address?

    An address set by software instead of the hardware maker. The U/L bit in the first byte is 1, so the second hex digit is 2, 6, A, or E. Virtual machines, containers, and phones with MAC randomization use them.

    Can a random MAC address conflict with a real device?

    Not if it is locally administered, because makers only ship universally administered addresses. Two random local addresses could match each other, but the odds are about 1 in 70 trillion per pair.

    What formats do MAC addresses come in?

    The same 12 hex digits are written as 00:1A:2B:3C:4D:5E (Linux, macOS), 00-1A-2B-3C-4D-5E (Windows), or 001a.2b3c.4d5e (Cisco).

    Often used together with MAC Address Generator.

    • MAC Vendor LookupNetwork Tools

      Organization name for a MAC prefix from the IEEE assignment list.