IPv4 vs IPv6
There are two versions of the Internet Protocol in everyday use, IPv4 and IPv6. They do the same job, but they look different and they exist for a good reason. This guide compares them in plain language.
Last updated: November 11, 2026
Quick comparison
The main differences are the length of the address and how it is written.
- IPv4 addresses are 32 bits long and written as four numbers from 0 to 255 separated by dots, for example 192.0.2.1.
- IPv6 addresses are 128 bits long and written as groups of hexadecimal characters separated by colons, for example 2001:db8::1.
- IPv4 allows about 4.3 billion addresses in total. IPv6 allows a vastly larger number, far more than the world will ever need.
Why IPv6 exists
The internet grew much faster than anyone expected when IPv4 was designed, and the supply of new IPv4 addresses has largely run out. Techniques such as network address translation let many devices share one public address, but they add complexity.
IPv6 solves the shortage by giving every network and device plenty of room for its own address. Internet providers and websites have been adopting it gradually for years.
How to read an IPv6 address
An IPv6 address has eight groups of up to four hexadecimal characters. To keep them short, leading zeros in a group can be dropped, and one run of consecutive all-zero groups can be replaced by a double colon.
For example, 2001:0db8:0000:0000:0000:0000:0000:0001 can be written as 2001:db8::1. The double colon can only be used once in an address, otherwise it would be unclear how many zero groups it replaces.
Dual stack: using both at once
Most networks today run IPv4 and IPv6 side by side, which is called dual stack. Your device prefers IPv6 when a website supports it and falls back to IPv4 when it does not.
This is why a lookup can show an IPv4 address on one network and an IPv6 address on another, or even different results on different websites.
Does it matter for privacy or speed?
Neither version is automatically more private. Many devices use temporary IPv6 addresses that change regularly, which helps, but websites can still see the network your address belongs to. Speed is usually similar, and any difference depends more on your provider than on the protocol.
How to check which one you use
Open the IP lookup tool and look at your detected address. If it contains dots, it is IPv4. If it contains colons, it is IPv6. The tool accepts both, so you can also paste any address to see its details.
Ready to try it? Open the IP lookup tool.