IP address
An IP address is the numeric label that identifies a device or network on the internet so that data can be routed to and from it.
What an IP address is
An IP address is a number assigned to a device or a network so that other machines know where to send data. Every packet that crosses the internet carries a source address and a destination address, in the same way that a letter carries the sender and the recipient. Routers read the destination, pass the packet one hop closer, and the reply comes back to the source.
There are two formats in use. IPv4 addresses look like 203.0.113.7 and are still the majority of what websites see. IPv6 addresses look like 2001:db8::1 and are slowly replacing them.
Public versus private addresses
The address a website sees is your public IP. It usually belongs to your internet provider, not to you, and it may change when your router reconnects. Inside your home or office, devices use private addresses such as 192.168.1.20 that are never routed on the internet. The router translates between the two using NAT, which is why one household shows a single public address.
Why it matters
Your public IP is the first thing a website learns about you, before any cookie or login. From it a site can look up the approximate location, the owning network (ASN), and whether the address belongs to a hosting company, a mobile carrier, or a consumer ISP. Fraud and bot-detection systems weigh all of these before they weigh anything else. If you route traffic through a proxy or VPN, the public IP is the address of that service, and everything the site infers about you starts from it.
How to check yours
The home page shows your current public address with its location and network. Use IP lookup to inspect any other address or hostname, and the IP checker to see every signal a website can derive from yours.
Common misconceptions
An IP address does not identify a person; it identifies a connection, often shared by many people. It also does not reveal a street address. City-level geolocation is an estimate based on where the provider uses the range, and it is regularly off by tens of kilometers.