Internet speed test
Measure download, upload and latency. The test talks to Cloudflare at speed.cloudflare.com/__down and speed.cloudflare.com/__up, and the random bytes carry nothing from your device.
- Download, upload, latency
- Free, no sign-up
The test talks to Cloudflare. It downloads from speed.cloudflare.com/__down and uploads random bytes to speed.cloudflare.com/__up. Those bytes carry nothing from your device.
Downloads from speed.cloudflare.com/__down and uploads random bytes to speed.cloudflare.com/__up. Those bytes carry nothing from your device. Free to use, no account. More device tests
How to use it
- Press Start test and leave this tab in front.
- Read download, upload and latency as each transfer finishes.
- Press Stop to end the test early.
What the three numbers mean
Latency is a short download from speed.cloudflare.com/__down, taken a few times, and the figure is the middle of those times. Download speed comes from larger downloads on that same address. Upload speed comes from sending random bytes to speed.cloudflare.com/__up. The bytes are made in this browser with crypto.getRandomValues, so the upload carries nothing from your device: no file, no page and no identifier.
The test talks to Cloudflare and runs one transfer at a time. When the answer names a Cloudflare edge, the page shows that code and the city from the colo list on this site. A slow link stays on the smaller transfer. Stop ends the transfer that is in flight. The numbers are for this path, at this moment, between this browser and Cloudflare.
Private by design
Privacy
The test talks to Cloudflare. Downloads use speed.cloudflare.com/__down and uploads use speed.cloudflare.com/__up. The upload is random bytes and they carry nothing from your device. The result stays on this page.
This page also shows Google ads, which can use cookies. Privacy and cookies explains how.
Questions
What does the internet speed test measure?
Download speed, upload speed and latency, from real transfers with Cloudflare.
What does the internet speed test send?
It downloads from speed.cloudflare.com/__down and uploads random bytes to speed.cloudflare.com/__up. The bytes are generated in this browser and carry nothing from your device.
Which server does it use?
The test talks to Cloudflare at speed.cloudflare.com. When the reply names an edge, the page shows that code and the matching city.
Can I stop a test?
Yes. Stop ends the transfer that is running. Start test begins a fresh set of readings.