Free MAC address lookup. Paste any MAC or OUI to identify the device vendor instantly from 38,000+ IEEE records. Batch lookup, all formats, no signup.
This MAC address lookup tool takes any MAC address — or just the first three octets of one — and tells you which manufacturer registered that block with the IEEE. It is the fastest way to answer the question every network administrator eventually asks: what is this unknown device on my network? Paste an address such as 3C:22:FB:00:11:22 and the tool returns the registered vendor (Apple, Inc.), the registration address on file with the IEEE, and a full structural breakdown of the address itself.
The lookup runs against a copy of the IEEE MA-L (MAC Address Block Large) registry containing 38,298 assignments, sourced from standards-oui.ieee.org. Queries are served from an edge database, so results come back in milliseconds with no rate limits, no account, and no captcha. You can look up one address, paste a list of hundreds for batch processing, dump raw ipconfig/arp/ip link output and let the tool extract every MAC it finds, or search the registry by vendor name to see every OUI a company owns.
A MAC-48 address is 48 bits — six octets, usually written as twelve hexadecimal digits. Those 48 bits split cleanly in half:
3C:22:FB:A1:B2:C3, the OUI is 3C:22:FB.Two bits inside the very first octet carry meaning of their own, and the tool decodes both:
| Bit | Name | Value 0 | Value 1 |
|---|---|---|---|
| Least significant bit of octet 1 | I/G (Individual/Group) | Unicast — one interface | Multicast — a group of interfaces |
| Second-least significant bit of octet 1 | U/L (Universal/Local) | Universally administered — IEEE-assigned, resolvable | Locally administered — software-set, not in any registry |
Practically, this means an address whose first octet has the value 2 in its second-lowest bit — addresses starting with 02, 06, 0A, 0E, x2, x6, xA or xE — was set locally and will never match a vendor. That is not a broken lookup; it is the correct answer.
ipconfig /all, ip link show, ifconfig, arp -a, a DHCP lease file, a switch MAC-address table. The tool finds every MAC address in the text and looks them all up at once.Different vendors and operating systems print the same address differently. All of these are the same interface, and the tool reads and emits every one of them:
| Notation | Example | Where you see it |
|---|---|---|
| Colon-separated | 3C:22:FB:A1:B2:C3 | Linux, macOS, most RFCs |
| Hyphen-separated | 3C-22-FB-A1-B2-C3 | Windows ipconfig, IEEE documents |
| Dot-separated (triplets) | 3c22.fba1.b2c3 | Cisco IOS, NX-OS |
| No separator | 3C22FBA1B2C3 | Log files, RADIUS, config exports |
Suppose an ARP table shows an unexpected client at B8:27:EB:9F:2C:41.
B8 is 10111000 in binary. The lowest bit is 0, so this is a unicast address. The second-lowest bit is also 0, so it is universally administered — an IEEE assignment, which means it is resolvable.B8:27:EB, which the registry attributes to the Raspberry Pi Foundation.9F:2C:41 is the board’s serial-derived identifier — unique per device, but meaningless outside the vendor.In thirty seconds you have gone from “unknown host” to “someone plugged a Raspberry Pi into the network,” which is a very different investigation from “an enterprise switch is misbehaving.” Newer Pi hardware ships under DC:A6:32 (Raspberry Pi Trading Ltd), and virtual machines commonly appear under VMware’s 00:0C:29 and 00:50:56 blocks — a fast way to spot a hypervisor guest in a list of physical hosts.
The tool also converts a 48-bit MAC into its 64-bit EUI-64 form and the IPv6 link-local address that stateless address autoconfiguration (SLAAC) derives from it. The transformation is mechanical:
FF:FE between them.fe80:: to get the link-local address.Because step 3 flips a bit, an IPv6 address seen in a packet capture will not textually contain the MAC that generated it, which trips people up constantly. Feeding the MAC through this converter shows exactly which fe80:: address to expect. If you also need to move between address families, the IPv4 to IPv6 converter handles the numeric side.
For the security side of an investigation, pair this with the IP reputation checker for the addresses those devices talked to, and the explainer on OUI and MAC vendor lookup for background on the registry itself.
The OUI is the first 24 bits (first three octets) of a MAC address, assigned by the IEEE Registration Authority to a specific organisation. It identifies who made the network interface. The remaining 24 bits are chosen by that manufacturer.
Three common reasons. First, the address is locally administered — randomised by a phone’s Wi-Fi privacy feature, set by a hypervisor, or configured by hand. These are not in any registry by design. Second, the OUI was assigned very recently and post-dates the registry snapshot. Third, the block is an MA-M or MA-S (medium and small) assignment, which subdivides a 28- or 36-bit prefix; this tool covers the 24-bit MA-L registry, which is the block type used by essentially all consumer and enterprise NICs.
No. A MAC address identifies a network interface’s manufacturer, nothing more. It carries no geographic, ownership, or subscriber information, and it is only visible within a single Layer 2 broadcast domain — routers rewrite it at every hop, so it never travels across the internet.
iOS and Android both default to per-network randomised (locally administered) MAC addresses to prevent cross-venue tracking. That is why a lookup on a phone’s Wi-Fi MAC often resolves to nothing. Disabling “Private Wi-Fi Address” on the device reveals the real, vendor-assigned address.
Batch mode has no fixed limit — paste a full switch MAC-address table if you like. Duplicate OUIs are deduplicated before the query, so a thousand Apple devices cost one lookup, and results export to CSV or JSON.
The registry snapshot holds 38,298 MA-L assignments taken from the IEEE public listing. Blocks registered after the snapshot will not resolve; if a lookup fails for a brand-new device, that is usually why.
MAC-48 is the 48-bit address burned into an Ethernet or Wi-Fi interface. EUI-64 is the 64-bit form used by IPv6 SLAAC, derived from the MAC by inserting FF:FE in the middle and inverting the U/L bit. The tool shows the derivation step by step.
The tool is free with no sign-up. Lookups query the OUI registry for the vendor name only; nothing you paste is retained or associated with you.
Its first octet is odd — the least significant bit is set. Familiar examples are 01:00:5E:xx:xx:xx (IPv4 multicast), 33:33:xx:xx:xx:xx (IPv6 multicast), and 01:80:C2:00:00:00 (spanning tree). The tool flags these so you do not chase a phantom device.
A MAC (Media Access Control) address lookup identifies the manufacturer of a network device by examining the first three octets (24 bits) of its 48-bit hardware address. Every network interface card (NIC)—whether in a laptop, smartphone, router, IoT device, or server—is assigned a globally unique MAC address at manufacture. The first half of this address is the Organizationally Unique Identifier (OUI), which maps to the device manufacturer.
MAC address lookup is a fundamental tool for network administration, security operations, and device inventory management. When you see an unknown device on your network, the OUI lookup tells you whether it is an Apple iPhone, a Dell server, a Raspberry Pi, or a Hikvision camera—providing immediate context for security decisions and troubleshooting.
A MAC address is a 48-bit identifier written as six pairs of hexadecimal digits: AA:BB:CC:DD:EE:FF. The IEEE (Institute of Electrical and Electronics Engineers) manages MAC address allocation:
| Portion | Bits | Name | Purpose |
|---|---|---|---|
| First 3 octets | 24 | OUI (Organizationally Unique Identifier) | Identifies the manufacturer |
| Last 3 octets | 24 | NIC-specific | Unique within the manufacturer |
Special MAC address types:
MAC randomization: Modern operating systems (iOS 14+, Android 10+, Windows 10/11) randomize MAC addresses when scanning for Wi-Fi networks and may use random addresses per network. This privacy feature means OUI lookups may return "Private" or "Locally Administered" for mobile devices.
A MAC (Media Access Control) address is a unique 48-bit identifier assigned to network interfaces by manufacturers. Written as six pairs of hexadecimal digits (e.g., 00:1A:2B:3C:4D:5E), the first three octets identify the manufacturer (OUI), while the last three are device-specific. MAC addresses operate at Layer 2 of the OSI model for local network communication.
OUI (Organizationally Unique Identifier) comprises the first 24 bits of a MAC address, identifying the manufacturer. IEEE assigns OUIs to hardware vendors who then assign unique device IDs. Companies like Apple (3C:06:30), Cisco (00:1E:14), and Intel (00:50:56) have multiple registered OUIs. Lookup tools use IEEE's public OUI database for identification.
Yes. While manufacturers assign MAC addresses, operating systems allow modification (MAC spoofing). This is useful for privacy, bypassing network restrictions, or testing. However, spoofing may violate network policies or laws in some jurisdictions. Most devices support changing MAC addresses through network settings or command-line tools, though some hardware has limitations.
Windows: Run "ipconfig /all" in Command Prompt, look for "Physical Address". Mac: System Preferences > Network > Advanced > Hardware, or run "ifconfig en0". Linux: Run "ip link show" or "ifconfig". Mobile devices: iOS Settings > General > About > Wi-Fi Address; Android Settings > About > Status > Wi-Fi MAC address. Each network interface has its own MAC.
Locally administered MAC addresses have the second-least significant bit of the first octet set to 1 (e.g., x2, x6, xA, xE in first octet). These are not globally unique and can be assigned by network administrators. Since iOS 14 and Android 10, devices use randomized private MAC addresses for Wi-Fi networks to enhance privacy.
Security teams use MAC lookup for network inventory (identifying unauthorized devices), forensics (tracking device manufacturers), access control (MAC filtering), rogue device detection, and incident response. While MAC addresses can be spoofed, lookup helps establish baseline inventory and detect anomalies. Combine with other factors for robust security rather than relying solely on MAC filtering.
MAC addresses are hardware identifiers assigned by manufacturers, permanent (though changeable), and work at Layer 2 for local network communication. IP addresses are logical identifiers assigned by networks, temporary (DHCP) or static, and work at Layer 3 for routing across networks. Devices need both: MAC for local switching, IP for internet routing.
IEEE updates the OUI database daily as manufacturers register new addresses. Public lookup tools should refresh their databases monthly minimum for accuracy. New device types (IoT, wearables) constantly emerge, requiring fresh assignments. The MA-L (24-bit OUI), MA-M (28-bit), and MA-S (36-bit) registries all receive regular updates from IEEE registration authority.
Batch lookup allows you to analyze multiple MAC addresses at once by entering them one per line or separated by commas. The tool automatically detects duplicates, showing you how many times each MAC appears, and processes up to 100 addresses in a single request. This is especially useful for network administrators analyzing network scans or device inventories.
Yes! The tool has a "Paste Network Output" mode that automatically extracts MAC addresses from ipconfig (Windows) or ifconfig (macOS/Linux) output. Just paste the entire command output, and the tool will find all MAC addresses, perform lookups, and detect any duplicates - perfect for quick network diagnostics.
EUI-64 (Extended Unique Identifier) converts a 48-bit MAC address into a 64-bit identifier used in IPv6 link-local addresses. The tool automatically generates the IPv6 address by inserting FF:FE in the middle of the MAC and flipping the 7th bit (U/L bit). This is essential for IPv6 networking and autoconfiguration.
The binary breakdown feature displays your MAC address in binary format, highlighting special bits like the I/G bit (Individual/Group for multicast) and U/L bit (Universal/Local for administration). This educational view helps you understand MAC address structure at the bit level and identify why certain addresses behave differently on networks.
No, absolutely not! Your lookup history is stored only in your browser's localStorage and never leaves your device. This privacy-first approach means your network investigation data stays completely private. You can clear your history at any time, and it's automatically limited to your 10 most recent lookups.
Type any vendor name (like "Apple" or "Cisco") and the tool automatically searches after you stop typing (300ms debounce). It queries our database of 38,000+ OUI entries and shows matching vendors with their assigned OUI prefixes. Click any result to instantly lookup a MAC address from that vendor.
When analyzing multiple MAC addresses (batch or network mode), duplicate detection automatically identifies MAC addresses that appear more than once and shows you the count. This is invaluable for finding devices with multiple interfaces, detecting network configuration issues, or identifying duplicated MAC addresses on your network.
Yes! The tool includes a random MAC generator with vendor selection. You can generate completely random MAC addresses or choose from 10 popular vendors (Apple, Cisco, Intel, etc.) to generate realistic MAC addresses using their actual OUI prefixes - perfect for network testing, simulation, or development work.