Private IP addresses in plain words
A private IP address is an address used only inside a local network, such as your home Wi-Fi, an office LAN or a mobile hotspot. Your router hands them out to phones, laptops, TVs and printers so they can talk to each other and to the router.
Because private addresses are not routed on the public internet, millions of networks can reuse exactly the same ones. Your laptop might be 192.168.1.20 at home, and someone on the other side of the world can have the same address on their network without any conflict.
When a device goes online, the router translates its private address into the shared public IP address, a process called network address translation or NAT.
The reserved private ranges
Three IPv4 blocks are reserved for private networks by the internet standard RFC 1918. Home routers usually use part of the 192.168 block, while large companies often use the 10 block because it has room for millions of devices.
IPv6 has a similar idea called unique local addresses, starting with fd. IPv6 devices also have link-local addresses starting with fe80, which only work on the same network segment.
- 10.0.0.0 to 10.255.255.255 (10.0.0.0/8): about 16.7 million addresses.
- 172.16.0.0 to 172.31.255.255 (172.16.0.0/12): about 1 million addresses.
- 192.168.0.0 to 192.168.255.255 (192.168.0.0/16): about 65,000 addresses.
- 100.64.0.0/10: shared address space used by carrier-grade NAT, not for home networks.
- 169.254.x.x: automatic link-local address, a sign that DHCP failed.
Private vs. public IP: the key differences
A public IP is unique on the internet and is what websites see. A private IP is unique only within your network and is invisible to websites. Your phone on home Wi-Fi therefore has both: a private address from the router and, through the router, the shared public address.
You can find your private address in your device network settings, and your public address on an IP lookup page. If an IP lookup ever shows a 192.168 or 10. address, something is wrong, because those addresses cannot travel across the internet.
Laptop 192.168.1.20 (private)
Phone 192.168.1.21 (private)
Smart TV 192.168.1.34 (private)
Router LAN 192.168.1.1 (private gateway)
Router WAN 203.0.113.45 (public, seen by websites)What 192.168.1.1 and 192.168.0.1 are
These are the most common default addresses for a home router. Typing one into a browser opens the router admin page, where you can change the Wi-Fi password, see connected devices and set up port forwarding. Other brands use 10.0.0.1, 192.168.100.1 or 192.168.8.1.
The fastest way to find yours is the “Default Gateway” value from ipconfig on Windows, or “Router” in the network details on Mac, iPhone and Android.
Change the default admin password on first login. Anyone connected to your Wi-Fi can reach that page.
Common private IP problems and fixes
An IP address conflict happens when two devices end up with the same private address, usually because one was given a manual address inside the router DHCP range. Fix it by setting devices back to automatic, or by reserving addresses in the router instead of typing them on the device.
A 169.254 address means the device did not get an address from the router. Restart the router and the device, check the cable or Wi-Fi password, and make sure the router DHCP server is enabled.
If you connect two routers, make sure they use different private ranges or put the second one in access-point mode; otherwise devices may get confusing double-NAT behaviour.