IPv4 vs IPv6: What Is the Difference?

IPv4 and IPv6 are two versions of IP addresses.

Both help devices communicate across networks. The main difference is address space. IPv4 is older and shorter. IPv6 is newer and supports a much larger number of unique addresses.

If you want to see which one your current connection is using, open the T.LY What Is My IP Address tool. It will show your public IPv4 or IPv6 address when available.

What is IPv4?

IPv4 is the older and more familiar IP address format.

An IPv4 address usually looks like this:

203.0.113.25

It uses four numbers separated by dots. Each number can range from 0 to 255.

IPv4 has been around for decades and is still widely used. The problem is that the internet grew far beyond what the original address space was designed to handle.

There are only about 4.3 billion possible IPv4 addresses. That sounds like a lot until you count phones, laptops, servers, routers, cloud infrastructure, smart TVs, watches, cameras, and everything else online.

What is IPv6?

IPv6 is the newer IP address format.

An IPv6 address looks more like this:

2001:db8:85a3::8a2e:370:7334

IPv6 addresses are longer and use hexadecimal characters separated by colons.

The biggest reason IPv6 exists is address space. It supports an enormous number of addresses, enough for the modern internet and far beyond.

Why do both still exist?

IPv6 did not replace IPv4 overnight because the internet is huge and backwards compatibility matters.

Many networks, servers, apps, routers, and ISPs still support IPv4. Many also support IPv6. Some support both at the same time, which is called dual stack.

That is why your connection might show:

• only IPv4
• only IPv6
• both IPv4 and IPv6

The What Is My IP Address tool checks the public address your current browser connection exposes.

Is IPv6 better than IPv4?

IPv6 solves the address shortage problem and was designed for a much larger internet.

That does not mean IPv4 is useless. IPv4 still works and is still everywhere. For most people, the difference is invisible during normal browsing.

IPv6 is useful because it:

• provides far more address space
• can reduce the need for some layers of address translation
• supports modern network growth
• lets more devices have globally routable addresses when networks allow it

IPv4 remains important because:

• many services still depend on it
• some networks do not fully support IPv6
• legacy systems and tools still expect IPv4
• many troubleshooting guides are written around IPv4 examples

How to tell if you are using IPv4 or IPv6

The fastest way is to check your public IP address.

Open What Is My IP Address. If your address contains dots, it is IPv4. If it contains colons and hexadecimal characters, it is IPv6.

Examples:

Version Example Easy clue IPv4 203.0.113.25 Dots IPv6 2001:db8::1234 Colons Some systems also show local network addresses in Wi-Fi or Ethernet settings. Those can be different from the public IP address websites see. If that is confusing, read Public vs Private IP Address: What Is the Difference?.

Does IPv6 change privacy?

IPv6 does not automatically make you anonymous or more private.

Websites can still see the public IP address used by your connection. Your browser, cookies, account logins, and device details can still be used for analytics and security.

Some IPv6 setups can make devices more directly addressable than old IPv4 home networks, but firewalls and router settings still matter. For most users, the practical privacy advice is the same:

• keep devices updated
• use trusted networks
• understand what your public IP reveals
• use a VPN when you need to route traffic through another network

To test whether a VPN changes the address websites see, compare your results in the T.LY IP checker with the VPN on and off.

Why a site may work on IPv4 but not IPv6

Sometimes a website, app, or network behaves differently over IPv4 and IPv6.

Possible reasons include:

• DNS records are missing or misconfigured
• the server supports one version but not the other
• a firewall rule blocks one protocol
• the ISP or local network has partial IPv6 support
• a VPN handles IPv4 and IPv6 differently

If you are troubleshooting a domain, the DNS Lookup tool can help you check A records for IPv4 and AAAA records for IPv6.

IPv4 vs IPv6 summary

IPv4 is the older address format with dotted numbers. IPv6 is the newer format with much more address space.

You do not need to memorize both formats to browse the web. But knowing the difference helps when you are troubleshooting a connection, setting up allowlists, checking DNS, or confirming whether a VPN is routing traffic correctly.

To see the public address your current connection is using, open the T.LY What Is My IP Address tool.