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Public vs Private IP Address: What "What's My IP" Actually Shows You
The difference between the public IP address websites see and the private address your device uses at home, and what an IP lookup can and cannot reveal.
Open a "what's my IP" page at home, then check your computer's network settings, and you will almost certainly see two different addresses. Neither is wrong. They are two different kinds of IP address doing two different jobs, and knowing which is which makes a lot of network problems easier to understand.
Private IP addresses: your address inside the house
Your router gives every device on your home or office network its own private IP address, usually something like 192.168.1.23 or 10.0.0.5. These addresses come from ranges reserved for private networks:
10.0.0.0to10.255.255.255172.16.0.0to172.31.255.255192.168.0.0to192.168.255.255
Millions of networks reuse the same private ranges, which is fine because these addresses never travel across the internet. They only need to be unique inside your own network, so your laptop, phone and printer can find each other and the router.
Public IP addresses: your address on the internet
Your internet provider gives your router a public IP address, which is unique on the internet. When any device in your home loads a website, the router swaps the device's private address for the shared public one, a process called network address translation (NAT). The website only ever sees the public address.
That is exactly what What's My IP shows you: the public address your requests appear to come from. Every device on the same home network will usually show the same public IP.
IPv4 and IPv6
The addresses above are IPv4, which has only about 4.3 billion possible addresses, not enough for every device on earth. That shortage is why NAT exists. IPv6 addresses, such as 2001:db8::1, are far longer and there are enough of them for every device to have its own public address. Many connections now use both, so you may see an IPv4 and an IPv6 address at the same time.
What an IP lookup can reveal
Look up a public IP with the IP Information tool and you will typically see the internet provider or organisation that owns it, and an approximate location. That location is usually accurate to the country and often to the region or city, but it is based on where the provider registers the address, not where you are sitting. It cannot show your street address or who you are.
You can also go the other way. IP to Hostname finds the name a server's owner has attached to an address, and Hostname to IP shows which address a domain points to.
Why your public IP changes
Most home connections have a dynamic public IP that the provider can change, for example when the router restarts. Businesses that run servers usually pay for a static IP that stays the same. Mobile data connections often share one public IP between many customers (carrier-grade NAT), which is why IP-based location can be surprisingly vague on a phone.
When this matters in practice
- Allowing access to a service by IP, such as a database or admin panel: use your public IP, and remember it may change.
- Setting up port forwarding for a game server or camera: the router forwards traffic from the public IP to a device's private IP. The Open Port Checker confirms whether the port is reachable from outside.
- Troubleshooting a website that works for others but not for you: your public IP may be blocked by a firewall. Our guide to checking whether a website is down walks through the steps.
For more address and domain utilities, browse the network tools.