IPv4 vs IPv6: What Is the Difference and Why It Matters

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IPv4 vs IPv6: The Internet Address Upgrade
Every device on the internet needs an IP address. IPv4 has been the standard since 1983, but the internet has outgrown it. IPv6 is the replacement. Here is what you need to know.
What is IPv4?
IPv4 addresses look like 192.168.1.1 — four numbers (0-255) separated by dots. This gives about 4.3 billion possible addresses. That sounded like plenty in 1983, but with smartphones, IoT devices, and a global internet population of 5 billion+, we ran out. Check your current IP to see if you are on IPv4 or IPv6.
What is IPv6?
IPv6 addresses look like 2001:0db8:85a3:0000:0000:8a2e:0370:7334 — eight groups of four hexadecimal digits. This gives 340 undecillion (3.4 x 10^38) possible addresses — enough for every grain of sand on Earth to have trillions of addresses.
Key Differences
Address size: IPv4 is 32-bit (4.3B addresses). IPv6 is 128-bit (340 undecillion)
Format: IPv4 uses decimal dots. IPv6 uses hexadecimal colons
NAT: IPv4 often uses NAT to share addresses. IPv6 gives every device a unique public address
Security: IPv6 has IPsec built-in. IPv4 added it as an afterthought
Speed: IPv6 can be slightly faster due to simpler routing headers
Privacy Implications
With IPv6, every device can have its own unique public address. This makes tracking easier unless you use IPv6 Privacy Extensions (enabled by default on most modern OS). A unique IPv6 address combined with your browser fingerprint makes you highly identifiable. Use a VPN to protect both your IPv4 and IPv6 addresses.
How to Check Your IP Version
Visit HackMyIP — we detect and display both your IPv4 and IPv6 addresses if available. You can also check if your ISP supports IPv6 by looking at your connection details.
Last updated: April 2026