Frequently Asked Questions about IPv6 and internet speed | IPv6 Speedtest

Our test measures three things: your download speed (how much data per second flows from the internet to your device), your upload speed (how much data per second flows from your device to the internet) and your ping (the delay in milliseconds between your device and the test server). The test is performed by nperf, a European platform with servers spread across Europe.

The test is very accurate, but the result depends on several factors:

• The distance to the nearest test server;
• Network load (other devices also using data);
• Whether you are testing over Wi-Fi or a wired connection;
• The capacity of your own device (processor, browser).

For the most accurate result, test via an Ethernet cable rather than Wi-Fi.

A speed slightly lower than the advertised maximum is normal. A few things to check:

• Test via Ethernet: Wi-Fi almost always has overhead and never reaches theoretical connection speeds.
• Restart your router: a simple restart often resolves temporary slowdowns.
• Check other devices: are there other devices using bandwidth during the test?
• Cable quality: a poor or old Ethernet cable can limit speed.
• Contact your provider if the speed is structurally too low.

IPv4 and IPv6 are both versions of the internet protocol, but differ significantly in address space and technical design:

• IPv4: 32-bit addresses (~4.3 billion), almost exhausted.
• IPv6: 128-bit addresses (~340 undecillion), more than enough for the far future.

Read more on our What is IPv6? page.

Not necessarily, but IPv6 can be faster in certain situations, because:

• There is no NAT overhead with IPv6 – packets travel directly from source to destination;
• IPv6 has a simpler header, making routing slightly more efficient;
• Some content providers (CDNs) have better IPv6 infrastructure than IPv4.

In practice, the difference is small for most users.

There are several ways:

• Run our speed test – the result will state which protocol was used.
• Visit test-ipv6.com for a comprehensive IPv6 diagnosis.
• Open Command Prompt (ipconfig /all on Windows) and check if there is an IPv6 address starting with 2001: or 2a00:.

IPv6 addresses are public and globally unique, without NAT. This means your device is theoretically directly reachable from the internet. Modern operating systems use privacy extensions (RFC 4941) that periodically generate a temporary, random address for outgoing connections – so your permanent address is not continuously visible. Check that privacy extensions are enabled on your system.

Yes, that is called dual-stack. Your device then has both an IPv4 and an IPv6 address. Connections are preferably established over IPv6; if that fails (for example, because a website does not yet support IPv6), the system automatically falls back to IPv4. You do not need to configure anything yourself.

No. We do not store IP addresses or individual test results. The speed test is performed by nperf; their privacy policy applies to the measurement data. Read our privacy policy for more information.

The speed test works in all modern browsers: Chrome, Firefox, Safari, Edge and Opera. Preferably use the latest version of your browser for the best results. Temporarily disable any VPN connections and browser extensions (such as ad-blockers) if the test does not start or appears incorrect.