Internet Speed Test
How fast your connection really is — and how much it slows down when it is busy.
Speed test
Latency while downloading — ms · while uploading — ms
Ready. A test takes about half a minute — up to two on slow connections.
The test connects to Cloudflare’s speed test servers (speed.cloudflare.com), which see your IP address. The results are sent to Cloudflare only if you tick the box; MySmartCoPilot receives nothing. Uses Cloudflare’s open-source engine.
Live measurements
Speed of each request
Latency samples
One dot per sample · the bar marks the median
Your result
Cloudflare WARP or Gateway is on, so this measures the connection through it rather than your provider’s line alone.
Latency and bufferbloat
What this connection handles
| Activity (one stream) | Needs | Your connection |
|---|
Bandwidth only, as the services publish it; add the figures up for several streams at once.
How long downloads take
Your results in this browser
No tests yet. Results are kept only in this browser.
| When | Download | Upload | Latency | Jitter | Loaded | Server | Delete |
|---|
About the Internet Speed Test
Press Start test to measure your connection’s download and upload speed, latency (ping) and jitter, and how much the latency rises while the line is busy — bufferbloat, the reason video calls stutter when someone starts a download. The test runs against the nearest data centre of Cloudflare’s global network with Cloudflare’s open-source measurement engine (the one behind speed.cloudflare.com), so no MySmartCoPilot server is involved.
Live charts show the speed of every request and every latency sample as they arrive. The result names the Cloudflare data centre that answered, the protocol and the data used, rates latency, jitter and bufferbloat, and checks the speeds against what Netflix, YouTube and Zoom say their services need. Past results stay in a history in your browser, to compare times of day, Wi-Fi and cable, or routers.
How to use it
- For the speed of the line itself, connect by cable if you can and pause downloads, streams and backups on other devices. For your real Wi-Fi experience, test where you normally sit.
- Choose Full test, or Data saver on mobile data or a metered connection, then press Start test. It takes about half a minute, and up to two minutes on slow connections.
- Watch the live charts: download and upload requests grow from 100 kB to up to 250 MB until each takes over a second, while latency is sampled the whole time.
- Read the result: speeds in Mbps (and MB/s), idle and loaded latency with the bufferbloat rating, the data centre, and which streaming and video-call qualities the line supports.
- Use Copy result to share it, or keep it in the history and Download CSV to compare tests over days.
Examples
Download 286 Mbps · Upload 93.4 Mbps Latency 8.1 ms (excellent) · jitter 1.2 ms While downloading: 11 ms — bufferbloat +2.9 ms (minimal)
Illustrative values. Enough for several 4K streams and HD video calls at the same time.
Download 48.2 Mbps · Upload 9.60 Mbps Latency 18 ms · while uploading: 212 ms — bufferbloat +194 ms (very high)
Illustrative values. The speeds are fine for streaming, but any upload (a photo backup, a video call) makes games and calls lag. Smart queue management on the router (FQ-CoDel, RFC 8290) usually fixes this.
Common uses
- Checking that you get the speed your broadband or fibre plan promises, and collecting evidence over several days before calling your provider.
- Finding out whether lag in games and video calls comes from bufferbloat rather than from slow speeds.
- Comparing Wi-Fi in different rooms, cable against Wi-Fi, a new router or mesh system, or a VPN on and off.
- Seeing whether a connection is good enough for 4K streaming, HD video calls or live streaming before you rely on it.
How the test measures
The page runs Cloudflare’s speed test engine (MIT licence, version 1.14.1) against speed.cloudflare.com and times every request with the browser’s Resource Timing API:
- Download and upload: files of 100 kB, 1 MB, 10 MB, 25 MB, 100 MB and 250 MB (uploads up to 50 MB) are transferred in turn. A direction stops growing once a set of requests takes more than a second each, so slow lines are not flooded. The speed shown is the 90th percentile of the individual request speeds.
- Latency: the median time to the first byte of empty requests, minus the time Cloudflare reports it spent on them. Jitter is the average change between consecutive latency samples.
- Loaded latency: latency samples taken while a download or upload is running. The increase over idle latency is the bufferbloat.
The engine’s optional packet-loss test needs a WebRTC TURN relay; Cloudflare has deprecated its public one, so packet loss is not measured here. The data centre comes from Cloudflare’s /cdn-cgi/trace and the HTTP version (HTTP/1.1, HTTP/2 or HTTP/3) from the browser’s own timing data, so the result shows the protocol your connection really used.
Latency, jitter and bufferbloat
Latency is the round trip to the server: what makes a web page feel snappy and decides lag in games and calls. Jitter is how much it varies; voice and video calls must buffer to hide it. Bufferbloat is latency that climbs while the line is full, because routers and modems hold too many packets in their queues — the IETF recommends active queue management to keep those queues short (RFC 7567).
The ratings use the bands of Cloudflare’s Aggregated Internet Measurement scoring, as implemented in the engine: latency and loaded-latency increase under 10, 20, 50, 100 and 500 ms (from excellent / minimal to very poor / severe), jitter under 10, 20, 100 and 500 ms. If bufferbloat is high, turn on smart queue management (SQM, FQ-CoDel or CAKE) in your router and set it a little below your measured speeds, use a cable, or ask your provider for a modem that manages its queue.
Why the result differs from your plan
- Wi-Fi is often the bottleneck: distance, walls, the 2.4 GHz band and neighbouring networks all cut speed. Test by cable to see the line itself.
- Other devices and apps share the connection: updates, cloud backups and streams on any device lower your result.
- Overhead: plans count raw bits, while a test can only measure the data inside the packets. On 100 Mbps Ethernet the most TCP can deliver is about 94.9 Mbps (RFC 6349, section 4.1.1), so 94 Mbps on a 100 Mbps plan is a perfect result.
- The server: this test measures to Cloudflare’s nearest data centre. Other tests use other servers and methods, so their numbers differ somewhat.
- Megabits and megabytes: 8 bits make a byte, so 100 Mbps downloads about 12.5 MB per second.
- VPNs and Cloudflare WARP add their own route and limits; the result says when WARP is on.
How much data a test uses
Because the engine stops each direction once requests take over a second, a Full test transfers more on faster lines: about 76 MB at 25/5 Mbps, 216 MB at 100/20 Mbps, 616 MB at 300/100 Mbps and up to 1.27 GB on gigabit fibre. Data saver never sends a request larger than 10 MB and uses at most about 86 MB. On fast connections the short transfers finish before TCP reaches full speed, so Data saver can read lower than a Full test. The live counter adds up the test’s downloads and uploads as each one finishes.
Bandwidth needed for common activities
The result checks your speeds against the services’ own figures, for one stream at a time — add them up for several devices:
- Netflix: 15 Mbps for Ultra HD 4K, 5 Mbps for Full HD (Netflix Help Center).
- YouTube: 20 Mbps for 4K, 5 Mbps for 1080p (YouTube Help).
- Zoom: 3.8 Mbps up and 3.0 Mbps down for 1080p video; 2.6 Mbps up and 1.8 Mbps down for a 720p group call (Zoom system requirements).
- YouTube Live: a recommended encoder bitrate of 14 Mbps for 1080p at 30 fps with H.264, which the upload has to carry (YouTube Help).
Limitations
- It measures from your browser to Cloudflare’s nearest data centre — not to a game server or website elsewhere, whose latency can be higher.
- Packet loss is not measured (the engine’s packet-loss test needs a TURN relay that Cloudflare no longer offers publicly).
- A single test is a snapshot: Wi-Fi, other devices, the time of day and browser extensions all change the result. Repeat it and compare in the history.
- On multi-gigabit lines the device, the browser or Wi-Fi can be the limit rather than the connection.
- The history is stored only in this browser and disappears if you clear the site’s data.
Privacy
The test runs between your browser and Cloudflare’s speed test servers at speed.cloudflare.com, which — like any server you connect to — see your IP address and the test traffic; Cloudflare’s privacy policy applies to them. The results are sent to Cloudflare only if you tick “Share results with Cloudflare”: the engine then posts the measurements (latency samples, the speed of each request and the quality scores) to speed.cloudflare.com/__results, which Cloudflare uses for its anonymous, aggregated Internet quality data. MySmartCoPilot receives nothing — no results and no IP address. Your history and settings stay in this browser’s storage until you clear them.
Frequently asked questions
What is a good internet speed?
It depends on what you do at the same time. Per stream, Netflix asks for 15 Mbps for 4K and 5 Mbps for Full HD, and Zoom 3.8 Mbps up and 3.0 Mbps down for 1080p video. A household that streams 4K on two TVs while someone is on a video call needs roughly 35 Mbps down and 4 Mbps up. For games and calls, low latency and little bufferbloat matter more than raw speed.
What is the difference between Mbps and MB/s?
Internet speeds are given in megabits per second (Mbps); downloads in browsers and apps usually show megabytes per second (MB/s). A byte has 8 bits, so divide by 8: 100 Mbps is about 12.5 MB/s, and a 1 GB file takes about 80 seconds. The result shows both.
What is bufferbloat and how do I fix it?
Bufferbloat is the extra delay that appears when your connection is busy: a router or modem keeps too many packets waiting in its buffers, so a game or call has to queue behind a download. The test shows it as the rise from idle to loaded latency. The usual fix is smart queue management (SQM with FQ-CoDel or CAKE) on the router, set slightly below your measured speeds.
Why is my upload much slower than my download?
Many plans are asymmetric by design: ADSL (the A stands for asymmetric), cable and mobile connections give far more capacity for downloading than for uploading. Fibre plans are often symmetric. Check your plan’s upload figure before assuming something is wrong.
Why does another speed test show a different result?
Each test measures to its own servers with its own method — how many parallel connections, which file sizes and how the result is averaged. This one measures to Cloudflare’s nearest data centre and reports the 90th percentile of request speeds. Small differences are normal; for a fair comparison run the tests one after the other on the same device and connection.
Does the test use a lot of mobile data?
A Full test uses about 76 MB on a 25/5 Mbps line and more on faster ones, up to about 1.3 GB on gigabit fibre — or fast 5G. Choose Data saver to stay under about 86 MB; it is selected for you when the browser reports mobile data or a data-saving mode (Chrome on Android reports the connection type), unless you picked Full test before. The data used is shown live and saved with each result.
Who sees my results?
Cloudflare runs the test servers, so it sees your IP address and the test traffic. It receives the results only if you tick “Share results with Cloudflare”. MySmartCoPilot sees nothing; your history is stored only in your browser.