IPv4 vs IPv6
See whether this request reached us over IPv4 or IPv6, understand what that observation proves, then compare the protocols. No sign-up, nothing to install.
IPv4 vs IPv6 at a glance
No column is highlighted until this request's route is observed.
| Feature | IPv4 Observed now | IPv6 Observed now |
|---|---|---|
| Introduced | 1981 | 1998 |
| Address length | 32 bits | 128 bits |
| Address format | Dotted decimal, e.g. 203.0.113.45 | Hexadecimal groups, e.g. 2001:db8::1 |
| Total addresses | About 4.3 billion | About 340 undecillion |
| Separator | Dots ( . ) | Colons ( : ) |
| Common deployment | Private addresses plus NAT are common; some providers also use CGNAT | Global addresses are common; firewalls still control unsolicited inbound traffic |
| Configuration | Manual or DHCP | Stateless auto-configuration (SLAAC) or DHCPv6 |
| IPsec | Available, but not automatic protection | Support is recommended, but traffic is not automatically secure |
| Base header | 20–60 bytes; options live in the header | Fixed 40 bytes; extension headers carry optional data |
| Broadcast | Uses broadcast | Replaced by multicast and anycast |
| Connection choice | A dual-stack client may use it when the IPv4 route wins | A dual-stack client may prefer it, then fall back if needed |
| Performance | Depends on the route, provider, and congestion | Depends on the route, provider, and congestion |
What is the IPv4 vs IPv6 tool?
IPv4 vs IPv6 is the question of how the internet labels every device that connects to it, and the two answers are two generations of the same idea. This page does two things on one screen. It observes the public address family selected for this request, and it lays out a clear comparison of the two protocols so you understand what that observation means. One request can prove that one route worked to this site; it cannot prove that the other family is unavailable. You get the live fact, its limit, and the background in a single glance, with no sign-up and nothing to install.
How to use it
- Open the page. It immediately asks our edge server for the public address selected for this request and shows it back to you.
- Read the badge next to the address. It identifies the route that reached this site as IPv4 or IPv6 without claiming the other family is unavailable.
- Tap copy to put the exact address on your clipboard for a firewall rule, an allowlist, or a support chat.
- Scroll to the responsive comparison to see how the observed family differs from the other one. Read it, get your answer, and move on.
The method behind it
A browser cannot read its own public address. The only honest way to learn the public value is to ask a server that received your request to echo it back, so this page calls a small same-origin endpoint at the edge that reads the connecting address and returns it. Once the address arrives, classifying it is deterministic: a colon-separated address is IPv6, while four valid decimal octets identify IPv4. We show only the route that actually reached this site. Modern dual-stack browsers can resolve both families and race connection attempts, so an IPv4 result does not prove IPv6 is unavailable, and an IPv6 result does not prove IPv4 is unavailable. Testing both capabilities requires separate IPv4-only and IPv6-only destinations, which this page deliberately does not contact.
The key differences
IPv4, introduced in the early 1980s, uses 32-bit addresses, which allows about 4.3 billion unique values. That sounded enormous at the time and turned out to be far too few for a planet of phones, laptops, servers, and smart devices. IPv6 uses 128-bit addresses, raising the pool to roughly 340 undecillion values — so large that address exhaustion stops being a practical concern. The two protocols also differ in notation, configuration, header shape, broadcast behavior, and common NAT deployment. Neither family is automatically secure or inherently faster: IPsec is available to both, ordinary traffic still needs appropriate security, and real speed depends on the provider, route, and congestion.
Examples
- Your result shows
203.0.113.45with an IPv4 badge: four dotted decimal groups, the classic format, meaning your connection reached us over IPv4. - Your result shows
2001:db8:85a3::8a2e:370:7334with an IPv6 badge: colon-separated hexadecimal groups, the newer format, meaning your connection reached us over IPv6. - A connection on a modern dual-stack network may show either family here because the browser selects from the routes that work for this destination.
Common use cases
- Learning the concrete difference between the two protocols before a networking exam, interview, or certification.
- Seeing which address family won for this request before using a separate dual-stack capability test when you need a complete diagnosis.
- Grabbing the exact address a server will see from you to paste into a firewall, allowlist, or database rule.
- Settling a debate about why some sites show a long colon address and others a short dotted one.
Why use this one
Most pages about IPv4 vs IPv6 are pure articles with no way to check your own connection, and most "what is my IP" pages echo a number without explaining what the selected family does or does not prove. This page gives you both at once: an honestly labelled observation of the route that reached this site, its dual-stack limitation, and a precise comparison tied to that result. It is private — the address is read once to show it to you and never logged or stored — and it stays minimal and mobile-friendly so you read your answer and go.
It is part of a small set for checking what your browser and connection reveal. To see your public IP from several sources at once, use What Is My IP; to read the identification string your browser sends, use What Is My User Agent; and to check the display your device reports, use What Is My Screen Resolution.
Frequently asked questions
Should I use IPv4 or IPv6?
For most people the choice is automatic. Your device, router, and provider negotiate whichever protocol both ends support, and modern networks often run both at once (dual-stack), preferring IPv6 when it is available and falling back to IPv4 when it is not. You rarely need to pick manually.
Is IPv6 faster than IPv4?
Not inherently. IPv6 can feel faster on some routes because it avoids extra NAT translation and uses a simpler header, but real-world speed depends far more on your provider, the path to the server, and congestion than on the protocol version itself.
Why don't I see my IPv6 address?
This page shows the address family selected for one request. Seeing IPv4 here does not prove IPv6 is unavailable: a dual-stack browser can support both families and still choose IPv4 for a particular destination. A true capability test must contact separate IPv4-only and IPv6-only endpoints.