How to use MAC Address Generator
The MAC Address Generator creates random 48-bit MAC addresses in any format: colon-separated (00:1A:2B:3C:4D:5E), dash-separated (00-1A-2B-3C-4D-5E), or without separators. Configure uppercase or lowercase hex, optionally set a vendor OUI prefix, and generate up to 100 addresses at once. All generation is local — nothing is uploaded.
- Choose the separator format: colon (:), dash (-), or none.
- Select uppercase or lowercase hexadecimal.
- Optionally enter an OUI prefix (e.g. 00:1A:2B) to fix the vendor identifier bytes.
- Set the count (1–100) for bulk generation.
- Click Generate and copy the addresses individually or all at once.
Your data never leaves your device — 100% private processing.
MAC address structure and format
A MAC (Media Access Control) address is a 48-bit (6-byte) unique identifier assigned to network interface controllers. It is conventionally written as six groups of two hexadecimal digits separated by colons or dashes (e.g. 00:1A:2B:3C:4D:5E). The first three bytes (24 bits) form the OUI (Organizationally Unique Identifier) assigned by the IEEE to manufacturers — allowing tools like Wireshark to resolve vendor names. The last three bytes are a device-specific serial number assigned by the manufacturer. Two special bits in the first byte matter: bit 0 (LSB) is the multicast bit — set to 1 for multicast addresses; bit 1 is the locally administered bit — set to 1 for MAC addresses not globally assigned by the IEEE, such as those used in virtual machines, containers, and randomised addresses.
| Format | Example | Common use |
|---|---|---|
| Colon-separated | 00:1A:2B:3C:4D:5E | Linux, macOS, network tools |
| Dash-separated | 00-1A-2B-3C-4D-5E | Windows, IEEE standard notation |
| No separator | 001A2B3C4D5E | Database storage, some APIs |
| Dot-separated (Cisco) | 001A.2B3C.4D5E | Cisco IOS notation (groups of 4) |
MAC address randomisation and privacy
Modern operating systems randomise the MAC address used for Wi-Fi scanning to prevent tracking. When your phone scans for networks, it broadcasts probe requests with a random locally administered MAC rather than its real hardware address. This prevents tracking your physical location across different networks based on your hardware address. iOS, Android, Windows 10+, and Linux all support MAC randomisation by default for Wi-Fi scanning; some also randomise the address used when connected to a network. For testing, generating random MAC addresses with locally administered bit set (second hex digit is 2, 6, A, or E) correctly simulates virtualised or randomised hardware addresses.
Worked examples
Random MAC, colon format
Inputs: separator : · lowercase
Result: 00:1a:2b:3c:4d:5e
Fixed vendor OUI
Inputs: OUI 00:1A:2B
Result: first 3 bytes fixed, last 3 random
Format variants
Inputs: the same address
Result: 00-1A-2B-3C-4D-5E or 001A.2B3C.4D5E (Cisco)
Glossary
- MAC address
- Media Access Control address — a 48-bit hardware identifier for a network interface, used for communication within a local network segment.
- OUI
- Organizationally Unique Identifier — the first 24 bits of a MAC address assigned by the IEEE to a manufacturer or organisation.
- Multicast
- Network communication addressed to a group of receivers; indicated in MAC addresses by the least significant bit of the first byte being set to 1.
- Locally administered
- A MAC address flag (second LSB of first byte = 1) indicating the address is locally assigned rather than globally unique from a manufacturer.
- NIC
- Network Interface Controller — hardware that connects a computer to a network; each NIC is assigned a globally unique MAC address by the manufacturer.
Related reading
Frequently Asked Questions
Why use MAC Address Generator?
- Generate random MAC addresses in colon, dash, or no-separator format for any platform
- Fix a vendor OUI prefix to simulate addresses from a specific network hardware manufacturer
- Bulk-generate up to 100 MAC addresses at once for network simulation or test data seeding
- Set the locally administered bit to produce valid virtual or randomised MAC addresses
Common use cases
- Generate dummy MAC addresses to populate a network simulation test fixture
- Create a locally administered MAC for a virtual machine interface in a dev environment
- Generate a vendor-specific MAC by fixing the OUI to a known manufacturer prefix for testing
- Produce a batch of random MAC addresses to seed a network inventory management database
- Generate a MAC address in Cisco dot-notation format for a router lab configuration file
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