Random MAC Address Generator
Create valid fake or dummy MAC address text for QA, VMs, containers, labs, simulations, and documentation. Local unicast is the safe default; bulk, vendor-prefix, range, format, and export options run entirely in your browser.
Your generated MAC address
Preparing a local unicast address…
Advanced options, bulk generation, and exports
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Generated batch
0 generatedThe output is bounded for easier mobile use.
How to generate a MAC address
- Use the default Local + Unicast result for ordinary test data, or open advanced options.
- Choose the type, administration bit, format, case, quantity, and optional prefix or range.
- Select Generate batch, verify the annotations, then copy or export TXT, CSV, or JSON.
This page only generates text values. It does not detect or change your device's real MAC address.
Worked examples
02:1A:73:C4:9B:20001A.2B3C.4D5EPractical uses
Populate repeatable-looking network records without copying production identifiers.
Exercise colon, hyphen, Cisco dotted, plain, uppercase, and lowercase parsing.
Create local unicast candidates for owned lab workloads, subject to platform policy.
Build unique-in-batch node lists or range-constrained datasets.
Create fictional client identifiers for screenshots, training, and examples.
Use clearly labeled dummy values rather than exposing a real adapter address.
MAC address technical reference
An EUI-48 value contains six octets (48 bits). In a universally administered address based on an IEEE MA-L assignment, the first three octets are the OUI and the assignment owner supplies the last three. Locally administered values are created under local policy instead.
flags
First 24 bits: IEEE OUI/MA-L or local prefix | Last 24 bits: organization-assigned identifier or random suffix
First-octet bit example
02 is binary 00000010. Reading the two rightmost bits, I/G is 0 (unicast) and U/L is 1 (local). The generator changes these bits only when no fixed prefix controls them.
Common formats
| Format | Example | Common use |
|---|---|---|
| Colon | AA:BB:CC:DD:EE:FF | Linux, macOS, logs, and general documentation |
| Hyphen | AA-BB-CC-DD-EE-FF | Windows interfaces and inventory exports |
| Cisco dotted | AABB.CCDD.EEFF | Cisco command-line interfaces |
| Plain | AABBCCDDEEFF | Databases, APIs, and compact identifiers |
Random space and collisions
With both the local and unicast bits fixed, 46 bits remain random: 246 possible values. A fixed 24-bit prefix leaves a 24-bit suffix: 224 possible values. Collision probability rises as a batch grows, particularly with a fixed prefix, so the generator uses strong browser randomness plus a Set and retries until every value in the current batch is distinct. That guarantee ends when the batch is replaced or exported.
Technical notes and limitations
- The IEEE Registration Authority assigns identifier blocks. Reusing a listed prefix here does not grant rights to that allocation or make the random suffix organization-issued.
- The generator uses
crypto.getRandomValues(), notMath.random(). Browser randomness and in-batch duplicate rejection improve generation quality but cannot coordinate with other devices or sessions. - Universal (UAA) describes the U/L bit state. Only an assignment owner following its allocation process can claim universal uniqueness; clearing the bit on random data is insufficient.
- Privacy-address features vary by platform and managed-network policy. Generated text is not a substitute for your operating system's supported configuration controls.
Sources:
Random MAC address FAQ
What is the difference between a locally and universally administered MAC address?
A locally administered address has the U/L bit set and is created by software or a network administrator. A universally administered address has that bit clear and is normally issued from an IEEE-assigned block by its owner. Clearing the bit on a random value does not make that value globally unique.
What happens when I choose a vendor OUI?
The selected 24-bit IEEE MA-L prefix is preserved and the address is generated as universal unicast. The vendor-looking result is test data; it was not issued by that manufacturer and must not be represented as one of its assigned device addresses.
Are the generated MAC addresses valid and unique?
Each result is a syntactically valid 48-bit value, and this tool prevents duplicates within the current generated batch. It cannot guarantee uniqueness across other devices, browser sessions, saved files, or networks.
Why does the first byte change with some settings?
The two lowest-order bits of the first octet encode individual/group and universal/local status. Without a fixed prefix, the generator sets or clears those bits to match your choices. Vendor and custom prefixes are preserved instead of being silently rewritten.
What is Cisco dotted notation?
Cisco dotted notation writes the 12 hexadecimal digits as three groups of four, for example 001A.2B3C.4D5E. It represents the same six-octet value as 00:1A:2B:3C:4D:5E.
Can I use these addresses for virtual machines or test data?
Local unicast addresses are the preferred default for disposable fixtures, owned lab systems, virtual machines, containers, simulations, and documentation. Check platform and network policies, and confirm that an address is unused before assigning it on a real network.
Does this tool change my device's real MAC address?
No. This page only generates text in your browser. It does not inspect, configure, or change any network adapter.
Why can vendor lookup fail for a randomized address?
Locally administered and privacy-randomized addresses are not manufacturer assignments, so their first 24 bits may not identify a vendor. Even vendor-looking test output only reuses a prefix and does not prove who made a device.