A free internet speed test that works in your browser
This internet speed test measures the three numbers that decide how your connection feels: download speed (how fast pages, videos and files arrive), upload speed (how fast your video-call picture, photos and backups leave) and ping (the round-trip delay to a nearby server, with jitter showing how much that delay wobbles). Results are in megabits per second (Mbps) and milliseconds.
The test runs against Cloudflare’s global speed-test network, which has servers in more than 300 cities, so you are usually measured against a point a few milliseconds away rather than across an ocean. It works the same way on fibre, cable, DSL, 4G/5G and public Wi-Fi, on phones and laptops alike, with no app, plug-in or sign-up. It also records latency while the download is running, which reveals bufferbloat — the lag spike that ruins calls when someone else in the house starts a big download.
How to use the Internet Speed Test
- Close downloads, cloud backups and video streams on this and other devices, so they do not share the line during the test.
- Press “Start speed test”. Ping is measured first with a burst of tiny requests, then the download runs for about ten seconds with several parallel streams.
- Leave “Include upload test” ticked to measure upload speed too; untick it on metered mobile data to save about 20–80 MB.
- Read the gauge and the four tiles, then the verdict that explains what the numbers mean for streaming, calls and gaming.
- Run the test two or three times, at different times of day, and compare the rows saved under “Previous results”.
Internet Speed Test features
Live animated gauge
The needle and arc follow the measured throughput in real time as the streams ramp up.
Ping, jitter and loaded latency
Median ping from ten probes, jitter as the average change between probes, and a separate ping measured during the download to expose bufferbloat.
Multi-stream download and upload
Four parallel download streams and three upload streams with growing request sizes find the real ceiling of fast fibre lines.
Nearest Cloudflare server
Shows the Cloudflare location (for example DEL, LHR or IAD) that answered, so you know what the test is measuring against.
Plain-language verdict
Tells you whether 4K streaming, HD video calls and online gaming will work well on this connection.
Result history
The last ten results are kept in your browser so you can spot slow evenings or compare before and after a router change.
What download, upload, ping and jitter mean
| Measure | What it tells you | Good value |
|---|---|---|
| Download (Mbps) | How quickly data reaches you — streaming, browsing, app updates | 25+ for 4K; 100+ for a busy household |
| Upload (Mbps) | How quickly data leaves you — video calls, backups, live streaming | 3+ per HD call; 10+ for creators |
| Ping (ms) | Round-trip delay to the server — responsiveness in games and calls | Under 30 excellent, under 80 good |
| Jitter (ms) | How much the ping varies — causes stutter and robotic voices | Under 10 excellent, under 30 fine |
| Loaded latency (ms) | Ping while the line is busy — reveals bufferbloat | Close to the idle ping |
Why speed test results vary
- Wi-Fi vs cable: Wi-Fi through walls can halve your speed; an Ethernet cable shows what the line itself delivers.
- Time of day: cable, DSL and mobile networks share capacity with your neighbours, so evenings are often slower than mornings.
- Other devices: a TV streaming 4K or a laptop syncing to the cloud takes bandwidth during the test.
- Device limits: old phones, USB adapters and busy laptops can top out below gigabit speeds even on a fast line.
- VPNs and proxies: traffic detours through another server, adding latency and often capping speed.
- Browser overhead: JavaScript tests lose a few percent to processing, so very fast lines may read slightly under their rated speed.
Mbps vs MB/s, and what your plan should deliver
Providers advertise in megabits per second, while download managers show megabytes per second. There are 8 bits in a byte, so a 100 Mbps connection downloads at most 12.5 MB/s — a 1 GB file in about 80 seconds. Use the Data Storage Converter to switch between units. Advertised speeds are usually “up to” figures; in the UK, Ofcom rules require a guaranteed minimum, and in India TRAI expects providers to publish typical speeds. If repeated wired tests come in far below your plan, note the results and contact your provider.
A slow result does not always mean a slow line. Check What Is My IP to confirm whether a VPN is active, and use the DNS Lookup tool if pages are slow to start loading even though downloads are fast — that points to DNS rather than bandwidth.
Internet Speed Test FAQ
How does this internet speed test work?
It sends ten tiny requests to the nearest Cloudflare server to measure ping and jitter, then downloads random data over four parallel streams for about ten seconds, and finally uploads random data over three streams. Throughput is calculated from the bytes transferred per second once the streams have ramped up.
What is a good internet speed?
For one person, 25 Mbps down and 3 Mbps up covers 4K streaming and HD calls. A family with several screens is comfortable at 100 Mbps or more. Gamers care more about ping (under 50 ms) and jitter than raw speed.
Why is my speed lower than what I pay for?
Wi-Fi distance, other devices, peak-hour congestion, an old router or a VPN are the usual causes. Test with an Ethernet cable and everything else idle to see the true line speed before contacting your provider.
Why is my upload speed so much lower than download?
Most cable, DSL and mobile plans are asymmetric by design, giving far more capacity to downloads. Fibre-to-the-home plans are often symmetric. Upload matters most for video calls, live streaming and cloud backups.
How much data does the test use?
A full run typically transfers 50–500 MB depending on your speed — faster lines move more data in the same ten seconds. The exact amount is shown after each test; untick the upload test to roughly halve it on a limited mobile plan.
Is the test accurate on mobile?
Yes. It runs in Safari and Chrome on iPhone and Android and measures the real 4G/5G or Wi-Fi throughput of the device. Mobile results vary more than fixed lines, so repeat the test a few times.
Is the speed test free and private?
Yes. There is no account and no app. The only traffic is the test data exchanged with Cloudflare’s servers, and your results are stored only in this browser.