Public vs private IP addresses
A public IP address is the one the rest of the internet sees. A private IP address is only used inside a local network such as your home or office, and cannot be reached directly from outside.
Public addresses
Your internet provider gives your router one public address. Some providers share one public address between several customers, so your router’s address can differ from the one websites see. Every website you visit sees that address. It is the one shown on the My IP page and the one a lookup tool can place on a map, roughly.
Private addresses
Your router hands out private addresses to the devices at home, such as your laptop, phone and printer. These are reserved ranges that are never used on the public internet:
- 10.0.0.0 to 10.255.255.255 (10.0.0.0/8)
- 172.16.0.0 to 172.31.255.255 (172.16.0.0/12)
- 192.168.0.0 to 192.168.255.255 (192.168.0.0/16)
How the two work together
When your phone asks for a web page, your router swaps the private address for the public one using network address translation (NAT), and swaps it back when the reply returns. This is why every device at home appears to a website as the same visitor.
Other special ranges
Addresses starting 127 are loopback (the device talking to itself), and addresses starting 169.254 are self-assigned when no server answers. Neither is reachable from the internet either.
Common questions
Why does my phone show a different IP address from this site?
Your phone shows its private address on your local network. This site shows your public address, the one your router uses for the internet.
Can someone reach my private IP address from the internet?
Not directly. Private addresses are not routed on the internet, and traffic only reaches them if your router has been set up to forward it.
Can two homes have the same private address?
Yes. Private addresses are reused everywhere, and 192.168.1.10 can exist in millions of homes at once.