What SpeedBench measures
SpeedBench is a free internet speed test that runs entirely in the browser: there is nothing to install and no account. The test traffic goes from your device to Cloudflare’s global network, which has servers in hundreds of cities, so the nearest one is usually close to you.
- Download: how fast data reaches you, in megabits per second (Mbps). It matters for streaming, downloads and opening websites.
- Upload: how fast you can send data. It matters for video calls, cloud backups, sending large files and streaming yourself.
- Ping: the time a tiny request takes to get to the server and back, in milliseconds. Lower is better for games and calls.
- Jitter: how much the ping varies from one request to the next. High jitter makes voice and video stutter.
- Latency under load and the bufferbloat grade: how much the ping grows while the connection is busy downloading or uploading.
- Connection details: your provider, the Cloudflare server city, the protocol, and whether you have working IPv6.
How to run the test
- Open SpeedBench and press Start. The test takes about half a minute.
- First it sends 20 tiny requests to measure ping and jitter.
- Then it downloads for about 10 seconds over four parallel connections. The first 1.5 seconds are ignored, because every connection needs a moment to speed up.
- Then it uploads for about 10 seconds over three connections.
- During both phases it keeps checking the ping about four times a second to measure latency under load.
- When the test ends, the result is saved to the history on this device, and you can share it as a link or save it as a picture, text, JSON or PDF.
On a mobile connection, or when the browser reports Data Saver, SpeedBench switches to Save mobile data mode on its own: the phases last 6 seconds and the whole test uses up to about 50 MB. The full test can use up to 500 MB of download and 200 MB of upload on a very fast line, although on such a line it usually ends sooner.
What the numbers mean
There is no single “good” speed: it depends on what you do online. As a rough guide:
| Activity | Download | Upload | Ping |
|---|---|---|---|
| Web, email, music | 5 Mbps | 1 Mbps | under 100 ms |
| HD video, one stream | 5–10 Mbps | 1 Mbps | any |
| 4K video, one stream | 25 Mbps | 1 Mbps | any |
| HD video call | 3 Mbps | 1.5–3 Mbps | under 100 ms |
| Online games | 10 Mbps | 3 Mbps | under 50 ms |
Multiply download by the number of people or screens that use the connection at the same time.
Ping and jitter
Under 20 ms of ping is excellent, 20–50 ms is good, 50–100 ms is fine for most things, and above 100 ms you may notice delays in games and calls. Jitter below 10 ms is good; above 30 ms, calls often break up.
Bufferbloat grade
Bufferbloat happens when a router or modem queues too much data: a large download makes everything else on the network slow, even if the speed itself is high. SpeedBench grades how much the ping grows under load:
| Grade | Ping increase under load | What it feels like |
|---|---|---|
| A+ | under 5 ms | no difference at all |
| A | 5–30 ms | calls and games stay smooth |
| B | 30–60 ms | barely noticeable |
| C | 60–200 ms | calls lag while someone downloads |
| D | 200–400 ms | web pages stall during uploads |
| F | 400 ms or more | the connection is nearly unusable under load |
A poor grade is usually fixed on the router, not by a faster plan: turn on SQM or Smart Queue (sometimes called QoS) if your router has it.
How to get an accurate result
- Use a cable if you can. Wi-Fi speed depends on distance, walls and neighbours’ networks. If you test over Wi-Fi, stand near the router and use the 5 GHz or 6 GHz band.
- Stop other traffic. Pause downloads, cloud sync, game updates and video on other devices in the house.
- Turn off the VPN unless you want to measure the VPN itself: it adds its own server to the route.
- Test several times at different hours. Evening speeds are often lower because more people are online.
- Compare with your plan. Providers sell speeds “up to” a figure; on Wi-Fi, getting 60–80% of the plan is normal.
Privacy and how it works
The fof.lol server only delivers the page. All test traffic goes from your browser straight to speed.cloudflare.com. To show your provider and city, SpeedBench asks a public IP lookup service (get.geojs.io, with ipwho.is as a fallback), and api6.ipify.org to check IPv6.
Results are stored only in this browser (up to 30 tests). A shared link contains the speeds, ping, jitter, the grade, the server, the provider and the chart, but not your IP address or location. Anyone who opens it sees a read-only copy.
Frequently asked questions
Why is my result lower than my plan?
Wi-Fi, other devices on the network, the VPN and the time of day all take their share. Test over a cable with nothing else running; if the speed is still far below the plan at different hours, show the saved results to your provider.
Why do different speed tests show different numbers?
Each service uses its own servers, number of connections and way of averaging. SpeedBench measures to the nearest Cloudflare data centre, which is close to how ordinary websites and apps reach you.
What is a good ping for gaming?
Under 50 ms with low jitter and a bufferbloat grade of A or B. The grade often matters more than raw ping: it shows what happens when someone else on the network starts a download.
Does the test use a lot of mobile data?
In Save mobile data mode the whole test uses up to about 50 MB. The mode turns on by itself on cellular connections, and you can switch it on manually.
Can I test the speed of my VPN?
Yes. Run the test with the VPN on and off and compare: the difference is the VPN’s cost in speed and latency.