Public vs. Private IP Addresses: Why Your Computer Has Two Different Numbers
If you open your computer's command prompt right now and type ipconfig (or ifconfig on Mac), you will probably see an IP address that looks like this: 192.168.1.5 or 10.0.0.2.
But if you go to a website to check your IP, it will show a completely different, random string of numbers, like 203.0.113.45.
Are you being hacked? Is your VPN leaking? No. You just have two different IP addresses. Here is why.
The Private IP (Your Inside Voice)
Your Private IP Address is assigned to your device by your home Wi-Fi router. It is only used inside your house (your Local Area Network, or LAN).
Think of your router like a receptionist at a massive office building. The receptionist’s desk is the only thing the outside world sees. But inside the building, every employee has a private extension number (like Ext. 101, Ext. 102).
Your phone, smart TV, and laptop all have private extension numbers (Private IPs). They use these numbers to talk to the router and to each other (like casting a YouTube video from your phone to your TV).
The Public IP (Your Outside Voice)
Your Public IP Address is assigned to your router by your Internet Service Provider (ISP). This is the address that the rest of the entire internet sees.
When you want to load a website like Google, here is what happens:
- Your laptop (Private IP:
192.168.1.5) asks your router for the website. - Your router takes that request, slaps your Public IP on it, and sends it out to the internet.
- Google sends the website data back to your Public IP.
- Your router remembers that your laptop asked for it, and forwards the data to your Private IP.
This brilliant system is called NAT (Network Address Translation). It is the only reason the internet hasn't completely run out of IPv4 addresses yet!
Why Does This Matter to You?
For everyday browsing, it doesn't. But you must know your Public IP if you ever want to:
- Host a Minecraft or web server from your house.
- Access your home security cameras while you are on vacation.
- Whitelist your home network so you can log securely into your company's remote server.
How to Find Your Public IP
Because your Public IP is what the outside world sees, your computer actually cannot tell you what it is on its own. You have to ask a server on the internet to look at you and report back what number it sees.
Want to know how the internet sees you right now?
