What Is the Difference Between IPv4 and IPv6? A Clear IPv4 vs IPv6 Comparison

If you have ever poked around your router settings, you have probably seen two odd-looking strings labeled IPv4 and IPv6. So what is the difference between IPv4 and IPv6, and does it actually change anything for you? In short: IPv4 and IPv6 are two versions of the same core internet protocol — the rulebook that lets devices connected to the internet find and talk to each other.

IPv6 is a newer standard built to fix the biggest limit of the older one: it was running out of addresses. This guide breaks down the comparison in plain language — address space, format, routing, security, and what the switch means for your everyday connection.

What Is IPv4?

IPv4 was the first version of internet protocol to be deployed at scale — version 4 of the standard — and it still carries most of the world’s traffic today. It uses a 32-bit address, written as four numbers in decimal and separated by dots — something like 192.168.1.1. That scheme allows about 4.3 billion unique addresses.

When IPv4 launched, roughly 4 billion internet addresses felt endless. Then smartphones, smart TVs, and connected gadgets arrived, and the pool started to dry up. To stretch supply, most networks lean on NAT — network address translation — which lets many devices behind one router share a single public address. It works, but it adds complexity to routing and can complicate direct connections between network devices.

What Is IPv6?

IPv6 is the more recent version of the internet protocol, designed by the Internet Engineering Task Force to solve the shortage for good. An IPv6 address uses a 128-bit format written in hexadecimal, with groups separated by colons — for example 2001:0db8:85a3::8a2e:0370:7334.

The jump in address length sounds small, but it is enormous. Where IPv4 eventually runs dry, IPv6 supports a pool so large it is effectively inexhaustible — enough unique IP addresses for every device on Earth many times over. Each address is 16 bytes long, and that larger address space is the whole point of the upgrade.

IPv6 also brings smarter defaults. It can assign its own address using stateless address autoconfiguration (SLAAC), so many devices get one without a central server handing them out. It can even build one from a device’s MAC addresses. When more control is needed, DHCPv6 does the job that DHCP handles on an IPv4 network.

IPv4 and IPv6 Compared, Point by Point

Here is the heart of the matter, side by side:

• Address space: IPv4’s addresses are short and cap the supply. IPv6’s format is far bigger, with a much larger address space.
• Format: IPv4 is decimal, dot-separated. IPv6 is hexadecimal, colon-separated.
• Address assignment: IPv4 requires DHCP (Dynamic Host Configuration Protocol) or manual setup. IPv6 can autoconfigure its own addresses.
• NAT: IPv4 relies on NAT to conserve public addresses. IPv6 has so many addresses available that NAT is largely unnecessary.
• Delivery types: IPv4 uses broadcast; IPv6 replaces it with multicast and anycast for cleaner one-to-many and one-to-nearest delivery.
• Security: IPsec was bolted onto IPv4 later; in the newer standard it was designed in from the start.

Address Space and Format: IPv4 and IPv6

The most visible difference between IPv4 vs IPv6 is how each address looks and how many exist. IPv4’s decimal, four-part format is easy to read but capped by its ceiling. Once you account for reserved ranges and private LANs, the true number of unique addresses left for public use is well under the theoretical maximum.

The newer numbering system changes the math entirely. Subnetting becomes simpler, subnets are huge, and there is room to give every home network — even every appliance — its own globally routable address. That is a real gift for the internet of things, where billions of IoT devices need to be online at once.

Want to see your own address in action? Our guide on how the internet works with addresses walks through the basics, and if you are curious what your router is using, here is how to find the IP address of your router.

IPv4 and IPv6: Headers, Routing, and Security

Under the hood, the packet header is where a lot of the improvement lives. The IPv4 header is variable and carries fields that a router must process on every hop. IPv6 uses a streamlined, fixed-size header that moves optional data into extension headers, so core routing gets lighter and packet flow can be faster on busy paths.

The newer protocol also handles quality of service more gracefully and supports built-in IPsec for encrypting internet communication between endpoints. For local addresses inside small networks, IPv6 has dedicated ranges, much like IPv4’s private space — but without those extra workarounds.

If you manage your own hardware, our explainer on VPN tunnels and how they work pairs well with this topic, since tunnels often carry both kinds of traffic together.

How the Two Standards Work Together

IPv6 and IPv4 are not directly compatible — a device speaking only the newer protocol cannot talk to an IPv4-only host on its own. To bridge the gap during this long migration, most ISPs run “dual-stack,” giving your connection both an IPv4 address and an IPv6 address at the same time. Your existing IPv4 setup keeps working while the newer standard grows alongside it.

Because the switch to an IPv6-only internet is gradual, the old IPv4 internet will stay important for years. This overlap is why the expansion of the internet has not simply broken older gear — the two standards coexist on the same wires.

Why IPv4 and IPv6 Matter for You

For most people, the standard protocol running underneath is invisible — you browse, stream, and game the same way regardless. But the version you use can affect how easy it is to be tracked. Some IPv6 setups can tie an address more directly back to a single device, which is worth knowing if privacy is a priority.

That is where a VPN helps. It replaces your visible IP address with one from its own network, whatever protocol your connection runs. If you want to control what the world sees, read how to change your IP address or how to hide your IP address with a VPN.

Stay Private on Any IP Version with Planet VPN

Whether your network runs IPv4, IPv6, or both, Planet VPN keeps your traffic protected with reliable encryption and masks the address others can see. The free plan gives you core protection across 6 locations at no cost — and if you want more locations and higher speed, Premium adds them without changing the fundamentals.

Download Planet VPN to get started, or compare Free and Premium plans to pick what fits your setup.

Frequently Asked Questions (FAQs)

What are the top 3 best practices for avoiding phishing attacks?

Check the sender’s real address before clicking anything, never enter passwords through links in unexpected emails, and turn on two-factor authentication so a stolen password alone is not enough. When a message pressures you to act fast, slow down — urgency is the classic phishing tell.

Which is better IPv4 or IPv6?

IPv6 is technically the better design: a far larger pool of addresses, simpler routing, and encryption built in. But “better” depends on context. IPv4 is more universally supported today, so for pure compatibility it still wins in many situations. Running both is usually the practical answer.

Does IPv6 make internet faster?

Sometimes, slightly. The cleaner header and absence of that translation step can reduce routing overhead, which may lower latency on some paths. In everyday use, though, your speed depends far more on your connection, your ISP, and the server you reach than on which IP version you use.

Should I enable both IPv4 and IPv6 on my router?

For most homes, yes. Dual-stack lets your router serve both an IPv4 address and an IPv6 address, so you stay compatible with the older internet while gaining the newer standard where it is available. It is the default on most modern routers for good reason.

What are the disadvantages of IPv6?

The main drawbacks are transitional. Some older gear and services still lack full support, addresses are harder to memorize, and a misconfigured setup can expose a device more directly if a firewall is not tuned. These issues fade as adoption grows.

Why is IPv6 not widely used?

Momentum. The existing setup already works, and NAT delayed the urgency by stretching the current supply. Upgrading hardware, software, and ISP infrastructure takes time and money, so adoption has been steady rather than sudden — though IPv6 use keeps climbing globally.

Is it good to prefer IPv4 over IPv6?

For maximum compatibility with older systems, preferring IPv4 can avoid occasional hiccups. But as more of the internet moves over, leaning on the newer standard — or simply running both — is the more future-proof choice for most users.