Internet Speed Test

Understanding your results

A speed test reports four numbers. Each one affects a different part of how your connection feels.

• Download speed (Mbps): how fast data reaches your device. It matters most for streaming, browsing, downloading files and game updates.
• Upload speed (Mbps): how fast your device sends data out. It matters for video calls, cloud backups and posting large files or videos.
• Ping (ms): the time a small message takes to reach the server and return. Lower is better, and it decides how responsive games and calls feel.
• Jitter (ms): how much that ping time changes from one moment to the next. High jitter causes choppy calls and lag spikes even when your speed looks fine.

Seeing different numbers on other speed tests? See why speed test results differ. Not sure whether your numbers are good? Read how much internet speed you actually need, learn what ping and jitter mean, or follow our checklist to improve a slow connection.

Is it enough for what you do? See whether your connection can handle 4K streaming, online gaming or video calls, or estimate your monthly data use.

Need more than a speed test? Try our free network tools: the bufferbloat and packet loss test, what is my IP address and the WebRTC leak test.

How this speed test works

CHECKiOX measures the connection between your device and the CHECKiOX server, directly: your browser downloads data from our server and uploads data to it, and nothing is routed through any other site. Ping and jitter come from a series of quick round trips. The download and upload tests use several connections at once, as the large speed tests do, and report the speed your line sustains once the first couple of seconds of ramp-up are over. Nothing is installed, and nothing from the test is stored on our side.

One thing to understand: CHECKiOX has a single test server and does not pick a nearby one for you. Your result is therefore accurate for the path between your device and that server. If you are far from it, or your provider's route to it is slow, you will see a higher ping and a lower speed than on tests that connect to a server inside your provider's network, such as Speedtest.net or Fast.com. Neither number is wrong: they measure different paths.

Frequently asked questions

Why is my speed lower than what my provider advertises?

Advertised speeds are usually the maximum under ideal conditions. Wi-Fi quality, distance from the router, other devices on the network, VPNs and busy evening hours all lower real results. Testing with a cable connected to your router shows what the line itself delivers.

Why is my CHECKiOX result different from Speedtest.net or Fast.com?

Because each test measures a different path. CHECKiOX runs from your device directly to the CHECKiOX server, and it has one server rather than a network of nearby ones. Speedtest.net and Fast.com choose a server close to you, often inside or near your provider's network, so on fast connections they usually read higher, especially if you are far from our server. The CHECKiOX figure is accurate for the connection between you and our server. To check that you get the speed you pay for, use a cable, pause other devices, and compare more than one test.

Why do my results change from test to test?

Internet speeds fluctuate with network congestion and with whatever else your devices are doing. Run the test two or three times, ideally with other downloads and streams paused, and look at the typical result rather than a single run.

Does the speed test use a lot of data?

Yes, a full test can transfer tens of megabytes or more, depending on how fast your connection is. If you are on a capped mobile plan, run it sparingly.

Is Mbps the same as MB/s?

No. Mbps means megabits per second, while MB/s means megabytes per second. There are 8 bits in a byte, so a 100 Mbps connection downloads at most about 12.5 MB/s.