IPv4 vs IPv6: What's the Difference?

Disclosure: This article contains affiliate links. We may earn a commission at no extra cost to you.

If you've ever checked your IP address on myip.foo, you might have noticed two types of addresses: IPv4 (like 192.168.1.1) and IPv6 (like 2001:0db8::1). But what's the difference, and why do we need two systems?

In this guide, we'll break down everything you need to know about IPv4 and IPv6 in simple terms—no networking degree required!

What is an IP Address?

Before diving into the differences, let's quickly explain what an IP address is. Think of it as your device's home address on the internet. Just like postal mail needs an address to reach you, data packets need your IP address to find your computer, phone, or smart device.

Every device connected to the internet has an IP address. When you visit a website, your device sends its IP address so the website knows where to send the data back.

IPv4: The Original Internet Protocol

IPv4 (Internet Protocol version 4) was introduced in 1983 and has been the backbone of the internet for decades. An IPv4 address looks like this:

How Many IPv4 Addresses Are There?

IPv4 uses a 32-bit address space, which means there are approximately 4.3 billion unique addresses available. That sounds like a lot, right?

Well, in 1983 it was. But as of 2025, we have over 15 billion internet-connected devices worldwide—smartphones, tablets, laptops, smart TVs, IoT devices, security cameras, you name it. We've officially run out of IPv4 addresses.

The IPv4 Address Shortage Problem

Back in the 1980s, nobody imagined we'd have billions of devices online. IPv4 was designed when the internet was mostly used by universities and research labs. Today, even your refrigerator might need an IP address!

To deal with this shortage, internet providers use a technique called NAT (Network Address Translation), where multiple devices share a single public IP address. It works, but it's a band-aid solution—not a permanent fix.

IPv6: The Next Generation

IPv6 (Internet Protocol version 6) was developed in the late 1990s to solve the address shortage problem. An IPv6 address looks quite different:

How Many IPv6 Addresses Are There?

IPv6 uses a 128-bit address space, which provides approximately 340 undecillion addresses. That's:

340,282,366,920,938,463,463,374,607,431,768,211,456

To put this in perspective: you could assign trillions of IP addresses to every person on Earth and still have plenty left over. We're not running out of IPv6 addresses anytime soon!

Key Differences: IPv4 vs IPv6

Why Haven't We Fully Switched to IPv6 Yet?

Great question! IPv6 was standardized in 1998—that's over 25 years ago. So why are we still using IPv4?

1. Compatibility Issues

IPv4 and IPv6 are not directly compatible. Websites, routers, and networks need to support both protocols, which requires upgrades and configuration changes.

2. Cost and Effort

Transitioning to IPv6 requires hardware upgrades, software updates, and retraining IT staff. For large organizations, this can be expensive and time-consuming.

3. NAT "Works Well Enough"

NAT has allowed IPv4 to survive much longer than expected. While not perfect, it's a workaround that keeps the internet running.

4. Gradual Adoption

As of 2025, about 45% of internet traffic uses IPv6 (according to Google). Major services like Google, Facebook, and YouTube fully support IPv6, and adoption is steadily growing.

Which One Should You Use?

The good news is: you don't have to choose! Most modern devices and networks support both IPv4 and IPv6 simultaneously (called "dual-stack"). Your device automatically uses whichever protocol works best for each connection.

How to Check Your IP Type

Want to see which IP protocol you're using? Here's how:

1. Visit myip.foo
2. You'll instantly see your IP address(es) displayed
3. Look for badges labeled "IPv4" or "IPv6"
4. If you see both, congrats—you have dual-stack connectivity!

You can also use our JSON API endpoint to programmatically check your IP type in scripts or applications.

The Future: IPv6 is Here to Stay

While IPv4 won't disappear overnight, the future clearly belongs to IPv6. Here's why:

• Internet of Things (IoT): Billions of smart devices need unique IP addresses
• Mobile networks: 5G networks are built with IPv6 in mind
• Better security: IPv6 has encryption built-in from the start
• No more NAT headaches: Every device can have its own public IP
• Improved performance: Simpler routing and auto-configuration

As more ISPs, websites, and services adopt IPv6, the transition will accelerate. Within the next decade, IPv6 will likely become the primary internet protocol worldwide.

Common Questions About IPv4 and IPv6

Can IPv4 and IPv6 communicate with each other?

Not directly. They require translation mechanisms or dual-stack networks (supporting both protocols) to work together.

Is IPv6 faster than IPv4?

In theory, IPv6 can be slightly faster due to more efficient routing. In practice, the difference is usually negligible for everyday users.

Is IPv6 more secure?

Yes! IPv6 has IPsec (encryption) built into the protocol, whereas IPv4 requires it as an add-on. However, security still depends on proper network configuration.

Will my old devices work with IPv6?

Most devices from the last 10-15 years support IPv6. Older devices might need firmware updates or may only support IPv4.

Conclusion

IPv4 and IPv6 are both essential parts of today's internet, each serving a specific purpose. IPv4 is the legacy system still powering much of the web, while IPv6 is the future-proof solution designed to handle billions of connected devices.

The good news? You don't need to worry about choosing between them—your devices and networks handle it automatically. Just enjoy your internet connection, and know that the transition to IPv6 is happening behind the scenes!