Guide
Public vs Private IP Addresses
A public IP can be reached on the internet. A private IP is used inside a local network and is not routed directly across the public internet.
Private ranges
Private addresses are common on home, office, and container networks. They let many devices share one public address through NAT.
If your laptop says it has 192.168.1.20, a website will usually see the public address of your router, VPN, or upstream gateway instead.
Why this matters
Public/private differences explain why a local device address rarely matches the address shown by a public IP checker.
They also explain why geolocation, ASN, and network owner information normally describe the internet-facing network rather than a private device.
Key terms
- NAT
- Network Address Translation
- RFC1918
- Common IPv4 private address ranges
- ULA
- Unique Local Address range for IPv6
Examples
Private IPv4
10.0.0.0/8
Common private network range.
Calculate this private range
Private IPv4
172.16.0.0/12
Common private network range.
Calculate this private range
Private IPv4
192.168.0.0/16
Common home router range.
Calculate this private range
Private IPv6
fc00::/7
IPv6 unique local address space.
Calculate this IPv6 range
Related guides and tools
FAQ
Why is my local IP different from ShowIP?
ShowIP sees the address that reaches the website. Your computer may have a private local address that is translated by a router or VPN before traffic reaches the internet.
Can a private IP be looked up globally?
No. Private ranges are reused by many networks, so they do not identify one public internet location.