What is an IP address?

The basics

An IP address (Internet Protocol address) is a unique numerical label assigned to every device connected to a computer network that uses the Internet Protocol for communication. It serves two core functions: identifying a host or network interface, and providing a location for that host in the network.

Think of it like a postal address for your device. Just as a letter needs a destination address to be delivered, data packets on the internet need an IP address to know where to go.

How are IP addresses assigned?

IP addresses are assigned by your Internet Service Provider (ISP) when you connect to the internet. Within your home or office network, your router assigns local IP addresses to each device using a protocol called DHCP (Dynamic Host Configuration Protocol).

There are two types of IP addresses:

• Public IP: The address your ISP assigns to your network. This is what the outside world sees — and what this tool shows you.
• Private IP: The address your router assigns to devices within your local network (e.g., your laptop, phone, smart TV). These are not visible to the internet.

Static vs. dynamic addresses

Most home internet connections use a dynamic IP address — one that can change each time you reconnect or periodically over time. Businesses and servers typically use static IP addresses that remain constant, making it easier for others to reliably reach them.

Two versions: IPv4 and IPv6

There are currently two versions of IP addresses in active use:

• IPv4 — the older, more common format, written as four numbers separated by dots (e.g., 203.0.113.42). Limited to about 4.3 billion addresses.
• IPv6 — the newer format, written as eight groups of hexadecimal numbers (e.g., 2001:0db8:85a3::8a2e:0370:7334). Supports a vastly larger address space.

This tool detects and displays both, if your connection supports them.