How to use
- Close other downloads.
- Press Start.
- Results show the median of the measurement window.
Worked example
A 100 Mb/s connection usually measures somewhat below 100 because of protocol overhead.
Supported formats and limits
| Output | Download, upload, latency, jitter |
|---|---|
| Limits | About 15 to 20 seconds and up to about 200 MB of transfer per test (160 MB down, 40 MB up). |
| Engine | Parallel HTTP transfers to speed.cloudflare.com with Resource Timing; measures after a warm-up period |
Limitations
- Results measure the path to Cloudflare's nearest location, not to every internet service.
- Mobile data is consumed.
Questions
What exactly is measured?
Latency is the median time of 20 small HTTP requests, and jitter is how much they vary. Download and upload speeds are the median of short measurement windows after a 2-second warm-up, from about 7 seconds of transfers in each direction.
Why is my result lower than my plan?
The test measures one path, from this browser to Cloudflare's nearest location, at one moment. Wi-Fi, other devices, browser overhead and protocol overhead all reduce the figure. It does not test your whole network or every service you use.
How much data does it use?
Up to about 160 MB down and 40 MB up per run, which counts against mobile data. Cloudflare sees your IP address, as with any website you visit.
Privacy
Uses a public service. Your browser sends only what is listed below (for example a domain name) to the named public service. No files or other content are sent.
- Cloudflare speed test (speed.cloudflare.com): Random test data to and from Cloudflare. Cloudflare sees your IP address, as with any website.
See the privacy policy for how toolsdocks handles data.