Internet Speed Test

How does this internet speed test work?

To measure your speed, the test downloads and then uploads blocks of data of increasing size between your browser and a Cloudflare test server close to you. It starts with small blocks, then moves on to bigger ones as long as the measurement is too short to be reliable: a slow connection only transfers a few megabytes, while fast fiber moves several hundred. The speed it keeps is the one your connection holds during its best transfers, not an average dragged down by the small files. The test also measures latency, which is the time a round trip to the server takes, first while the connection is idle and then during the transfers. Everything happens in your browser, on this page, with no app to install and no account to create.

Mbps, ping, jitter: how to read your results

Download speed is how fast you receive data: it matters for watching videos, loading web pages and downloading files. Upload speed is how fast you send data: it matters for video calls, sharing photos and online backups. Both are shown in megabits per second (Mbps). Watch out for bits and bytes: file sizes are measured in megabytes (MB), and 1 MB/s equals 8 Mbps. So a 100 Mbps connection downloads at most about 12.5 MB per second. Latency, or ping, is the time a round trip to the server takes, in milliseconds (ms): the lower it is, the snappier your connection feels. Jitter is how much that latency changes from one moment to the next: when it's high, calls and games stutter even if your speed is good. Finally, latency under load, measured during a big transfer, shows whether your connection falls apart as soon as someone in the house starts a big download.

What internet speed do you need for 4K, video calls, gaming and working from home?

For 4K video, streaming services usually ask for 15 to 25 Mbps per stream; HD (1080p) gets by with about 5 Mbps. An HD video call on Zoom, Teams or FaceTime needs little bandwidth, around 3 to 4 Mbps each way, but above all low latency, low jitter and decent upload speed, which is often the weak spot of DSL and some cable plans. Online games use very little bandwidth: what counts is low ping (under 50 ms to play comfortably) and low jitter. Working from home combines all of this, with video meetings, remote access and large shared files: 25 Mbps down and 10 Mbps up is comfortable. The tool compares your results with these thresholds and shows “Good”, “Borderline” or “Not enough” for each use, along with the weak spot when there is one. Keep in mind that your speed is shared between every connected device in the house. On a phone, 4G LTE and 5G speeds change a lot from one place to another: run the test in the room where you actually use your phone.

Why is my internet slower than it should be? Wi-Fi, router and connected devices

The speed your internet provider advertises is a maximum, measured on the line, not in your living room. Wi-Fi is the main reason for the gap: the distance to the router, walls, neighbors' networks and the band you use (5 GHz is faster but has a shorter range than 2.4 GHz) can eat up a big part of your speed. To find out the true speed of your line, test over Ethernet, then compare with Wi-Fi. Other things play a part too: devices downloading at the same time, a VPN that's turned on, a browser loaded with extensions, peak evening hours, or an old computer whose network card caps the speed. Run the test two or three times, because a single result can land at a bad moment. Finally, remember that this test measures the link to a nearby Cloudflare server: with a website hosted far away or overloaded, your real speed may be lower.