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

Q: What is the difference between IPv4 and IPv6?

IPv4 is 32-bit and uses decimal addresses like 192.168.1.1, giving about 4.3 billion possible addresses. IPv6 is 128-bit and uses hexadecimal addresses like 2001:0db8:85a3::8a2e:0370:7334, giving 340 undecillion addresses. IPv6 also has IPsec security built in and gives every device a unique public address, while IPv4 often relies on NAT to share addresses.

Q: Is IPv6 safer or more private than IPv4?

Not inherently. IPv6 has IPsec defined as part of the protocol, but in everyday use it can be less private by default because every device gets a globally unique, directly reachable address rather than hiding behind NAT as IPv4 often does. The fix is IPv6 privacy extensions, which rotate a temporary address so your IPv6 is not a permanent tracking identifier. With privacy extensions enabled, IPv6 privacy is roughly comparable to IPv4.

Q: Is IPv6 better than IPv4?

In most technical respects, yes. IPv6 offers a virtually unlimited address space, built-in IPsec security, and can be slightly faster thanks to simpler routing headers. The main trade-off is privacy: because every device can have its own unique public IPv6 address, tracking is easier unless you use IPv6 Privacy Extensions, which are enabled by default on most modern operating systems.

Q: Why do we need IPv6 instead of IPv4?

IPv4's roughly 4.3 billion addresses seemed limitless in the 1980s but are not nearly enough for today's billions of smartphones, IoT devices, and a global internet population of 5 billion-plus. IPv6 was created to solve that shortage with 340 undecillion addresses, enough for every grain of sand on Earth to have trillions.

Q: Should I use IPv4 or IPv6?

You generally do not have to choose: most devices and networks now support both. IPv6 brings a larger address space and built-in IPsec, but combined with your browser fingerprint, a unique IPv6 address can make you more identifiable, so using a VPN to protect both your IPv4 and IPv6 addresses is wise.

Q: Can IPv4 and IPv6 work together?

Yes. The transition from IPv4 to IPv6 is ongoing, and most devices now support both at the same time, which is why HackMyIP can detect and display your IPv4 and IPv6 addresses together when both are available.

~/sheets/ipv4-vs-ipv6.md

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.
Frequently Asked Questions
What is the difference between IPv4 and IPv6?
IPv4 is 32-bit and uses decimal addresses like 192.168.1.1, giving about 4.3 billion possible addresses. IPv6 is 128-bit and uses hexadecimal addresses like 2001:0db8:85a3::8a2e:0370:7334, giving 340 undecillion addresses. IPv6 also has IPsec security built in and gives every device a unique public address, while IPv4 often relies on NAT to share addresses.
Is IPv6 better than IPv4?
In most technical respects, yes. IPv6 offers a virtually unlimited address space, built-in IPsec security, and can be slightly faster thanks to simpler routing headers. The main trade-off is privacy: because every device can have its own unique public IPv6 address, tracking is easier unless you use IPv6 Privacy Extensions, which are enabled by default on most modern operating systems.
Why do we need IPv6 instead of IPv4?
IPv4's roughly 4.3 billion addresses seemed limitless in the 1980s but are not nearly enough for today's billions of smartphones, IoT devices, and a global internet population of 5 billion-plus. IPv6 was created to solve that shortage with 340 undecillion addresses, enough for every grain of sand on Earth to have trillions.
Should I use IPv4 or IPv6?
You generally do not have to choose: most devices and networks now support both. IPv6 brings a larger address space and built-in IPsec, but combined with your browser fingerprint, a unique IPv6 address can make you more identifiable, so using a VPN to protect both your IPv4 and IPv6 addresses is wise. Check which version your connection uses.
Can IPv4 and IPv6 work together?
Yes. The transition from IPv4 to IPv6 is ongoing, and most devices now support both at the same time, which is why HackMyIP can detect and display your IPv4 and IPv6 addresses together when both are available.
Is IPv6 safer or more private than IPv4?
Not inherently. IPv6 has IPsec defined as part of the protocol, but in everyday use it can be less private by default because every device gets a globally unique, directly reachable address rather than hiding behind NAT as IPv4 often does. The fix is IPv6 privacy extensions, which rotate a temporary address so your IPv6 is not a permanent tracking identifier. With privacy extensions enabled, IPv6 privacy is roughly comparable to IPv4.
Published: May 2026