IPv4 vs IPv6: What's the Difference and Which One Am I Using?

If you've ever looked up your IP address and seen two completely different-looking strings of numbers and letters, you're not seeing an error. You're looking at IPv4 and IPv6, the two addressing systems the internet runs on, often at the same time.

Here's the short version: IPv4 looks like four numbers separated by dots (192.168.1.1), IPv6 looks like a longer string of numbers and letters separated by colons (2001:0db8:85a3::8a2e:0370:7334), and most devices today use both at once. Check what is my IP address here and you'll likely see both listed side by side.

What IPv4 actually is

IPv4 is the original addressing system the internet was built on, and it's still the most widely used format today. Each IPv4 address is made up of four numbers between 0 and 255, separated by periods. The problem with IPv4 is simple math: there are only about 4.3 billion possible addresses, and the world has far more devices than that connected to the internet now.

That shortage is the entire reason IPv6 exists. If you want a full walkthrough of how to read and check your own IPv4 address, see your current IPv4 address here.

What IPv6 actually is

IPv6 was built to solve the address shortage. Instead of four short numbers, it uses eight groups of characters, giving it a number of possible addresses so large it's practically limitless for the foreseeable future. It also handles routing more efficiently, which is part of why newer networks are gradually shifting toward it.

Not every network supports IPv6 yet, which is why you might see one on your phone but not on an older office network. For more on how this shows up on dual-stack networks specifically, read the full IPv6 breakdown.

Why you might see both at the same time

Most modern internet providers and devices run what's called a dual-stack setup, meaning your device gets both an IPv4 and an IPv6 address at once and uses whichever one a given website or app supports. This is completely normal and not something to fix. If a site only supports IPv4, your device falls back to that one automatically.

This is also why running a lookup tool sometimes shows an IPv6 address and sometimes shows only IPv4: it depends on what the site or app you're connecting through actually supports at that moment.

How to tell which one you're currently using

The fastest way is to look up your IP address here, which will show both formats if your connection supports them, clearly labeled. If you'd rather check manually on your own device:

• Windows: run ipconfig in Command Prompt and look for both IPv4 Address and IPv6 Address listed under your active connection.
• Mac: go to System Settings > Network > your active connection, where both formats are listed if available.
• iPhone and Android: tap the info icon next to your connected Wi-Fi network, where IPv4 and IPv6 addresses are shown separately if both are active. For the full steps on each device, see the complete device-by-device guide.

Does it matter which one I'm using?

For everyday browsing, no. Both formats get you online, and your device switches between them without you needing to do anything. It matters more if you're setting up port forwarding, hosting a server, or troubleshooting a connection issue where a website or service specifically requires one format over the other.

Frequently asked questions

Is IPv6 more secure than IPv4? IPv6 includes some security features built into the protocol itself, but in practice, security depends far more on your network setup and software than on which IP version you're using.

Why does my IP address ipv4 and ipv6 look so different in length? IPv4 addresses are short because they were designed decades ago for a much smaller internet. IPv6 addresses are longer because they needed to support a far larger number of possible devices.

Can I have an IPv6 address but no IPv4 address? It's uncommon but possible on IPv6-only networks. Most home and mobile connections still assign both, which is why checking your IP address here usually shows both formats together.

What is my ip address ipv4 ipv6 format supposed to look like? IPv4 format is four numbers from 0-255 separated by periods, like 192.0.2.1. IPv6 format is eight groups of characters separated by colons, like 2001:0db8:85a3::8a2e:0370:7334. Run a quick IP lookup to see your own version of each.