Every IP address falls into one of two camps: public (visible to the internet) or private (hidden inside a local network). The distinction shapes how the internet actually works. Here's the clean explanation.

What public IPs are

Public IPs are globally unique and routable. Every device that talks directly to the internet needs one. Web servers, email servers, your home router — all have public IPs. Your ISP assigns the public IP to your router.

What private IPs are

Private IPs are reserved ranges that don't route on the public internet. They only work inside a local network. Your phone, laptop, and printer all use private IPs to talk to each other and to your router. The router translates these to its single public IP when reaching out.

The reserved private ranges (RFC 1918):

• 10.0.0.0 – 10.255.255.255 (16.7 million addresses)
• 172.16.0.0 – 172.31.255.255 (1 million addresses)
• 192.168.0.0 – 192.168.255.255 (65,000 addresses)

Why we have both

IPv4 only has 4.3 billion addresses — not enough for every device. Private ranges plus NAT let one public IP serve hundreds of devices behind it. Without this, the internet would have run out a decade earlier.

How to tell which is which

If your IP starts with 10., 172.16-31., or 192.168., it's private. Anything else is public. Our IP checker shows your public IP. Your phone's Settings → Wi-Fi shows the private IP your router gave you.

Other reserved ranges worth knowing

• 127.0.0.0/8 — localhost
• 169.254.0.0/16 — APIPA, self-assigned
• 100.64.0.0/10 — carrier-grade NAT (mobile)

Try it now

Curious what your IP is showing the world right now? Check your IP address & location instantly with our free tool — no signup, nothing stored. Or trace any other IP to see its geolocation, ISP, and network details.