What does the MAC Address Generator actually randomize?

It fills all 6 bytes of the address with cryptographically random values from the Web Crypto API, unless you supply a vendor prefix — then only the octets after the prefix are randomized.

What is a locally administered MAC address?

It's an address with the second-least-significant bit of the first byte set to 1, marking it as assigned by an administrator rather than a hardware vendor. The MAC Address Generator's toggle sets this bit (and clears the multicast bit) so the result is guaranteed unicast and safe to use without clashing with real hardware.

Can the MAC Address Generator keep a specific vendor prefix?

Yes. Enter an OUI like 00:1A:2B in the prefix field and the generator keeps those exact leading octets, randomizing only the remaining bytes.

Which MAC address formats does the tool support?

Colon-separated (00:1a:2b:3c:4d:5e), dash-separated (00-1a-2b-3c-4d-5e), Cisco dot-quad (001a.2b3c.4d5e), and a plain unseparated string, in upper or lower case.

Are the generated MAC addresses sent to a server?

No. The MAC Address Generator runs entirely in your browser using your device's random number generator. No addresses or prefixes you enter ever leave your device.

Can I generate more than one MAC address at a time?

Yes. Set the count field to however many addresses you need and the generator produces that many, one per line, ready to copy.

MAC Address Generator Online

Generate random or vendor-prefixed MAC addresses in colon, dash, Cisco, or plain format, right in your browser.

The MAC Address Generator runs entirely in your browser. Any prefix you type and every address it generates stay on your device and are never uploaded to ArrayKit.

Open the CIDR Calculator

About MAC Address Generator

MAC Address Generator creates one or many 6-byte hardware addresses on demand, formatted with a colon, dash, Cisco-style dot, or no separator at all. Give it a vendor OUI prefix like 00:1A:2B and it keeps those leading octets while randomizing the rest, so the result still looks like it came from a real manufacturer block. Turn on the locally-administered toggle and it forces the unicast and locally-administered bits on the first byte, producing a safe address that will never collide with a real vendor assignment — ideal for lab gear, VM templates, and test rigs. Network engineers, QA teams, and anyone provisioning virtual NICs or documenting hardware use it to fill out configs and spreadsheets fast. Every byte comes from your device's cryptographic random number generator, and nothing is ever uploaded.

Features

Generates cryptographically random 6-byte MAC addresses
Optional vendor OUI prefix keeps the leading octets fixed
Colon, dash, Cisco dot-quad, or no-separator output formats
Uppercase or lowercase hex rendering
Locally-administered (unicast) toggle forces safe, non-vendor bits
Generate a batch of addresses at once, one per line
One-click copy of the full list
Runs entirely in your browser using the Web Crypto API

How to use the MAC Address Generator

Set how many MAC addresses you need
Optionally enter a vendor prefix such as 00:1A:2B
Pick a separator, case, and whether to force locally-administered bits
Click Generate and copy the list

Example

Input

random, colon, uppercase

Output

3D:F2:9A:1C:04:B7

Common errors & troubleshooting

The vendor prefix is rejected or ignored. — Enter only hex digits, optionally separated by colons, dashes, or dots (e.g. 00:1A:2B). The MAC Address Generator uses up to the first 6 bytes it can parse.
A generated address gets rejected as invalid by other software. — Some tools require the locally-administered bit to be set on any non-vendor address. Enable 'Locally administered (unicast)' so the first byte's low bits are 0b10.
Cisco device config won't accept the address format. — Switch the separator to Cisco dot-quad, which formats the address as three 4-hex groups like 001a.2b3c.4d5e instead of six 2-hex octets.
Two generated addresses in the same batch look too similar. — That is expected when you supply a vendor prefix — only the unprefixed octets are randomized, so leading bytes repeat across the batch by design.

Frequently asked questions

What does the MAC Address Generator actually randomize?: It fills all 6 bytes of the address with cryptographically random values from the Web Crypto API, unless you supply a vendor prefix — then only the octets after the prefix are randomized.
What is a locally administered MAC address?: It's an address with the second-least-significant bit of the first byte set to 1, marking it as assigned by an administrator rather than a hardware vendor. The MAC Address Generator's toggle sets this bit (and clears the multicast bit) so the result is guaranteed unicast and safe to use without clashing with real hardware.
Can the MAC Address Generator keep a specific vendor prefix?: Yes. Enter an OUI like 00:1A:2B in the prefix field and the generator keeps those exact leading octets, randomizing only the remaining bytes.
Which MAC address formats does the tool support?: Colon-separated (00:1a:2b:3c:4d:5e), dash-separated (00-1a-2b-3c-4d-5e), Cisco dot-quad (001a.2b3c.4d5e), and a plain unseparated string, in upper or lower case.
Are the generated MAC addresses sent to a server?: No. The MAC Address Generator runs entirely in your browser using your device's random number generator. No addresses or prefixes you enter ever leave your device.
Can I generate more than one MAC address at a time?: Yes. Set the count field to however many addresses you need and the generator produces that many, one per line, ready to copy.

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