Internet Speed Test
Download, upload and latency in about 20 seconds, then what that speed can actually do, and whether your line stays responsive when it is busy.
Uses roughly 50 MB to 1 GB of data per direction, depending on your speed. Results are measured between your browser and Cloudflare's network and stay on this device.
How it works
Four parallel HTTPS connections pull and push data for 8 seconds each. The first second is ignored while speed ramps up; the rest is averaged. Latency is probed the whole time.
Why it can read low
Browsers, Wi-Fi distance, VPNs, extensions and other devices all cost throughput. For a fair number, test on Ethernet with other downloads paused.
Speed is only half
Fast plans still stutter in calls and games if latency spikes or drops. Follow up with the stability test.
What the numbers mean
Download
How fast data reaches you, in megabits per second (Mbps). It decides how many things can stream at once and how long large downloads take.
Upload
How fast you can send data. Video calls, cloud backups and sharing large files depend on it, and it is usually much lower than download.
Latency
How long a small request takes to come back, in milliseconds, while the line is idle. Lower is better for anything interactive.
Under load
How much latency rises while the line is busy downloading or uploading. Under 30 ms extra is grade A, under 60 ms B, under 150 ms C, under 300 ms D, and anything more is F.
How much speed do you need?
| Activity | Rule of thumb |
|---|---|
| One 4K stream | About 25 Mbps download for each stream |
| HD streaming | At least 5 Mbps download |
| HD group video calls | About 10 Mbps download and 5 Mbps upload |
| One-to-one HD video call | About 2 Mbps upload |
| Everyday work from home | About 10 Mbps download |
| Cloud work and large uploads | About 25 Mbps download and 5 Mbps upload |
These are the practical guidelines this page uses to describe your result, not guarantees. Several people sharing a connection add their needs together.
What this test does not tell you
- It measures the path between your browser and Cloudflare's network, not the route to one particular website, game server or streaming service.
- It is one moment in time. Speeds often drop in the evening when your neighbourhood is busy, so test again when the problem actually happens.
- On Wi-Fi it measures your Wi-Fi as well as your line. Test once on Ethernet to see which of the two is the limit.
- Speed says nothing about dropouts. For those, use the stability test or the continuous monitor.
Speed test questions
- Why is my speed lower than the plan I pay for?
- Plans are sold as "up to" speeds measured at the modem. A browser test also includes your Wi-Fi, your device, browser extensions, any VPN, and whatever else is using the connection at that moment. Test on Ethernet with other downloads paused; if it is still far below your plan at several times of day, that is worth raising with your provider.
- How much data does the speed test use?
- It depends on your speed, because the test runs for a fixed time rather than a fixed size: 8 seconds of download and 8 seconds of upload. That is roughly 50 MB on a slow line and up to 1 GB per direction on a very fast one, which is where it stops. Avoid it on metered or mobile data.
- How does this speed test work?
- It opens four parallel HTTPS connections to Cloudflare's speed-test endpoint, downloads for 8 seconds and then uploads for 8 seconds. The first moment of each phase is ignored while the speed ramps up, and the rest is averaged. Latency is measured before the test and again while each phase is running.
- What does the "under load" grade mean?
- It compares your latency while the line is busy with your latency when idle. A big rise means your router queues traffic badly, a problem usually called bufferbloat. It is why a fast connection can still lag in a call or a game whenever someone else starts a download.
- Are my results stored anywhere?
- Only in this browser. Your recent speed tests are kept on your own device so you can compare them, and you can delete them at any time. Nothing is uploaded to our servers.