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**A MAC address is 48 bits (6 bytes) long.**

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## Short version for an interview

> **The length of a MAC address is 48 bits, that is 6 bytes.**

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## In detail, in plain language

### What this looks like in practice

48 bits are usually written:

- in **hexadecimal format**
- 2 characters per byte

Example:

```
AA:BB:CC:DD:EE:FF
```

Every two characters = **1 byte**
In total:

- 6 pairs → 6 bytes → 48 bits

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## What these 48 bits consist of

A MAC address is logically split into two parts:

1. **The first 24 bits (3 bytes)** - the OUI
the manufacturer identifier
2. **The last 24 bits (3 bytes)** - a unique device number

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## An important nuance (for extra credit at an interview)

There are also:

- **64-bit MAC addresses (EUI-64)**

They are used:

- in some technologies
- for example, when forming IPv6 addresses

But the **classic MAC in Ethernet is always 48 bits**.

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## Quick comparison

| Address | Length |
|---|---|
| MAC (Ethernet) | 48 bits |
| IP v4 | 32 bits |
| IP v6 | 128 bits |

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## Summary

> **A standard MAC address is 48 bits (6 bytes) long** and is used at the data link layer to address devices on a local network.

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