A private IP address, from 10.0.0.0/8, 172.16.0.0/12 or 192.168.0.0/16, is used inside a local network and isn't reachable from the internet. A public IP address is globally unique and routable; your router uses one for your whole network and translates with NAT.
How it works
Private ranges (RFC 1918)
- 10.0.0.0/8: 10.0.0.0–10.255.255.255, about 16.7 million addresses (big companies, some routers).
- 172.16.0.0/12: 172.16.0.0–172.31.255.255 (Docker uses part of this).
- 192.168.0.0/16: 192.168.0.0–192.168.255.255 (most home routers).
Anyone can use these, so millions of homes use 192.168.1.x at the same time. Routers on the internet drop them.
Public addresses
Assigned by regional registries to ISPs and organisations. Websites see your public IP, and so does everything else on the internet.
Other special ranges
100.64.0.0/10 (carrier-grade NAT), 127.0.0.0/8 (loopback), 169.254.0.0/16 (link-local). In IPv6, fd00::/8 is the private-like unique local range, but most devices simply get public IPv6 addresses.
Side by side
| Private IP | Public IP | |
|---|---|---|
| Example | 192.168.1.23 | 203.0.113.7 |
| Scope | Your local network | The whole internet |
| Unique | Only within your network | Globally |
| Assigned by | Your router (DHCP) | Your ISP |
| Reachable from internet | No | Yes (subject to firewall) |
| Find it on a Mac | System Settings › Network | curl -s https://api.ipify.org |
Examples
- At home: Mac 192.168.1.23 (private), router's internet side 203.0.113.7 (public).
- In an office: laptop 10.40.12.87 (private), office public IP 198.51.100.20.
On a Mac
- Private:
ipconfig getifaddr en0, or System Settings › Network › Wi-Fi › Details. - Public:
curl -s https://api.ipify.orgin Terminal.
See it in the app
LightAtom's Map shows where your public traffic goes and counts private-address connections separately as Local network.
Frequently asked questions
What is the difference between a public and private IP?
A private IP works only inside your local network; a public IP is unique on the internet and is what websites see.
What are the private IP ranges?
10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16.
Is 192.168 a public IP?
No. Every 192.168.x.x address is private.
Can someone find me from my public IP?
They can see your ISP and approximate city, not your exact address. Only your ISP can map it to you.