What Is an IP Address?

Learn what an IP address is, how public and private IPs work, and why websites use addresses to send data back to your device.

An IP address is a number used to identify a device or network connection so data can move across the internet. Without IP addresses, websites would not know where to send the pages, images, and files you request.

The concept is easier to understand when you separate public IP addresses used on the internet from private IP addresses used inside local networks such as homes, offices, and routers.

How IP addresses move data

When you open a website, your device sends a request through your network. Routers use IP addresses to move that request to the destination and return the response to the correct connection.

Public and private addresses

Public IP addresses are reachable on the internet. Private IP addresses are used inside local networks and are commonly hidden behind a router using network address translation.

IPv4 and IPv6 formats

IPv4 addresses look like four numbers separated by dots. IPv6 addresses are longer and use hexadecimal characters separated by colons to support a much larger address space.

Why IP addresses change

Many residential and mobile networks use dynamic addresses. Your public IP can change when your ISP rotates it, your router reconnects, you switch networks, or you use a VPN.

Frequently Asked Questions

Is an IP address the same as a device name?

No. A device can have a name, a local private IP, and a public IP route. These are related but not the same.

Can two people share one public IP?

Yes. Homes, offices, mobile carriers, VPNs, and shared networks can place many users behind one public IP address.

Why do websites need my IP?

They need a return address for your connection so requested pages and data can be delivered back to your browser.