What Is IPv4?
IPv4 (Internet Protocol version 4) is the fourth version of the Internet Protocol and the first to be widely deployed. It uses a 32-bit address format, which means there are approximately 4.3 billion possible unique addresses. An IPv4 address looks like four groups of numbers separated by dots — for example, 192.168.1.1 or 74.125.224.72.
How IPv4 Addresses Work
Every device connected to the internet needs a unique address so other devices know where to send data. Your ISP assigns your router a public IPv4 address, which is the one websites and services see when you connect. Inside your home network, your router assigns private IPv4 addresses to each device (like 192.168.0.x or 10.0.0.x).
When you visit a website, your browser sends a request from your public IPv4 address to the website's server. The server processes the request and sends data back to your IPv4 address. This happens billions of times per second across the global internet.
IPv4 Address Format
An IPv4 address consists of four octets (groups of numbers), each ranging from 0 to 255, separated by periods. Here's how to read one:
192.168.1.100Each number (192, 168, 1, 100) represents 8 bits of a 32-bit address. Together they create a unique identifier for your device on the network.
Why Are IPv4 Addresses Running Out?
The 4.3 billion available IPv4 addresses seemed like plenty when the protocol was designed in the 1980s. But with billions of smartphones, computers, IoT devices, and servers now connected, the pool of available IPv4 addresses has been effectively exhausted. This is why IPv6 was created — it uses 128-bit addresses, providing a virtually unlimited supply.
IPv4 vs IPv6 at a Glance
| Feature | IPv4 | IPv6 |
|---|---|---|
| Address Length | 32 bits | 128 bits |
| Format | 192.168.1.1 | 2001:0db8:85a3::7334 |
| Total Addresses | ~4.3 billion | ~340 undecillion |
| Adoption | Universal | Growing (~40%) |
How to Check Your IPv4 Address
The easiest way is to use our IP lookup tool — it shows your public IPv4 address instantly. You can also find it through your device settings: