Public vs Private IP Address: What's the Difference?
If you have ever noticed that your phone says one IP address while a website says another, you have seen the difference between a private and a public IP address.
Public IP address
A public IP address is assigned by your internet provider and is the address the rest of the internet sees. Websites, games and apps you connect to see this address. Every device on your home network shares it. You can see yours on our My IP page.
Private IP address
A private IP address is used only inside your local network (home, office, school). Your router assigns them with DHCP. They cannot be reached directly from the internet, and the same private address is reused in millions of networks.
Reserved private IPv4 ranges
| Range | CIDR | Typical use |
|---|---|---|
10.0.0.0 – 10.255.255.255 | 10.0.0.0/8 | Large organizations, some routers |
172.16.0.0 – 172.31.255.255 | 172.16.0.0/12 | Medium networks, Docker |
192.168.0.0 – 192.168.255.255 | 192.168.0.0/16 | Most home routers |
Other special addresses include 127.0.0.1 (loopback, your own device), 169.254.x.x (link-local, used when DHCP fails) and 100.64.0.0/10 (carrier-grade NAT).
How NAT connects the two
Network Address Translation (NAT) runs on your router. When your laptop (192.168.1.20) opens a website, the router swaps the private source address for the public one and remembers the connection. When the reply returns, it forwards the data back to the right device.
Why your router's WAN IP may differ from your public IP
Some mobile and broadband providers use carrier-grade NAT (CGNAT): many customers share one public address. If the "WAN IP" in your router starts with 100.64–100.127 or does not match what our tool shows, you are probably behind CGNAT. This is also why port forwarding and hosting from home may not work on some connections.
Can you look up a private IP?
No. Private addresses have no public location or ISP, so a lookup tool can only report that the address is private. Public IPs can be checked with the IP lookup tool.