What is an IP address?

An IP address is the number the internet uses to deliver data to the right device, in the way a postal address lets a letter reach the right house.

The short answer

Every device that talks on a network needs an address, so that replies can find their way back. On the internet that address is an IP address ("Internet Protocol address"). When you open a website, your phone or computer sends a request that carries two addresses: where it is going (the website's server) and where it came from (you). The server sends the page back to the second one.

You do not choose this number. Your internet provider, or the Wi-Fi router you are joined to, hands it to your device automatically when you connect.

What an IP address looks like

There are two kinds in use today.

IPv4: four numbers from 0 to 255 with dots between them, such as 203.0.113.25. This is the older kind and still the most common.
IPv6: up to eight groups of letters and digits with colons between them, such as 2001:db8:85a3::8a2e:370:7334. It was made because the world ran short of IPv4 addresses.

Many connections now have both at once. The home page shows which ones your connection is using at this moment.

You usually have two addresses, not one

This surprises most people. At home, your router has one public address, given by your internet provider. That is the address websites see. Inside the house, the router gives each phone, laptop and television its own private address, such as 192.168.1.7. Private addresses work only inside your own network. Our guide to public and private addresses explains how the two fit together.

What your IP address tells a website

Roughly where you are. Usually the country and often the city or region of your internet provider's equipment. It is not your street address, and it can be wrong by hundreds of kilometres, especially on mobile data.
Who your internet provider is. Blocks of addresses are registered to companies, and those records are public.
Nothing about who you are. Your name, phone number and home address are not in an IP address. Only your internet provider can link an address and a time to a customer, and it shares that only when the law requires it.

Does my IP address stay the same?

Often it does not. Most home and mobile connections get a dynamic address that can change when the router restarts, or every few days or hours. A static address, which never changes, is normally a paid extra for businesses. See static and dynamic addresses.

Common questions

Is an IP address the same as a MAC address?

No. A MAC address is fixed into the network part of a device and is used only on the local network. An IP address is given by the network you join and changes when you move to another network.

Can two devices have the same IP address?

Not on the same network at the same time: that causes an "IP conflict" and one of them loses its connection. But millions of homes use the same private addresses, such as 192.168.1.1, because private addresses never leave the house.

Is it safe that websites can see my IP address?

It is how the internet works; no page could reach you without it. The risks are small and are covered in our guide on what someone can do with your IP address.