Public vs Private IP Address: What's the Difference?
Every home network uses two kinds of IP address. A public address identifies your whole connection to the internet, and private addresses identify each device inside your home. Understanding the split explains why you cannot simply connect to a laptop from across the world, and why port forwarding exists.
Public IP address
This is the address websites see when you visit them. Your internet provider assigns it to your router, and every device on your network shares it. It is unique on the internet at any moment, and it is what our IP checker displays.
Private IP address
Private addresses are used only inside local networks, so they can be reused by millions of homes without clashing. Your router hands them out to your phone, laptop and TV. Three IPv4 ranges are reserved for this:
| Range | CIDR | Typical use |
|---|---|---|
10.0.0.0 – 10.255.255.255 | 10.0.0.0/8 | Large companies, 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 ranges you may meet include 127.0.0.1 (your own device, called loopback), 169.254.x.x (self-assigned when DHCP fails) and 100.64.0.0/10 (used by providers for carrier-grade NAT).
How the two work together
Your router performs network address translation (NAT). When your laptop requests a web page, the router replaces the laptop's private address with the public one, remembers who asked, and forwards the reply back to the right device. Unsolicited traffic from the internet has no matching entry, so the router drops it. That is a useful side effect: NAT acts as a basic shield.
What about IPv6?
With IPv6 most devices receive a globally routable address, and the router's firewall is what blocks unwanted inbound traffic instead of NAT. IPv6 also has private-style ranges: unique local addresses (fc00::/7) and link-local addresses (fe80::/10). See IPv4 vs IPv6.
Why it matters
- Hosting from home. To reach a game server or camera from outside, you have to forward a port from the public address to a private one. Read what port forwarding is.
- Privacy. Websites see only your public address, never the private ones behind it.
- Troubleshooting. If the router's WAN address differs from the public address you see online, your provider is probably using carrier-grade NAT.
Try it yourself
See the real numbers for your own connection with our free tools.