Internet speed test

Measure your connection’s download and upload speed, ping and jitter from your browser. The test runs OpenSpeedTest 2.5.4, hosted on zerobounce.ai, and measures the path from your device to Cloudflare’s network, where zerobounce.ai runs. It needs no app or plugin and works in any current browser on a phone, tablet or computer.

How the test works

• Ping and jitter: 10 small requests answered by Cloudflare’s network (not the test server code); ping is how long a round trip takes, and jitter is how much it varies.
• Download: your browser fetches random data over 6 parallel connections, one to each of six test addresses on zerobounce.ai, for about 12 seconds.
• Upload: your browser sends random data over 12 parallel connections, 24 streams at a time, for about 12 seconds.
• Both speeds include OpenSpeedTest’s default 4% allowance for protocol overhead.

Reading the result

The figures show what your device and connection can do to Cloudflare’s network right now, not your plan’s ceiling. Wi-Fi, VPNs, other traffic on your network and busy devices all lower them, so run the test again on a wired connection to compare. If the server doesn’t answer within 5 seconds, the test stops with a network error.

Questions

Why does the speed test use several connections?

One connection rarely fills a fast line. Measured from a test machine about 40 ms from Cloudflare, one upload connection topped out at 110–130 Mbps, and with 0.2% packet loss 24 streams reached 407 Mbps where 6 reached 117. So the download runs 6 streams, one on each of six test addresses (s1–s6.speed.zerobounce.ai), and the upload 24 streams over twelve. Each stream runs in a small hidden frame on its own address; if a frame doesn’t load within 8 seconds, its streams go to zerobounce.ai itself.

How often can I run the test?

Each 30 MiB piece of test data is one request, and each network (one IPv4 address or one IPv6 /48) can make 1,000 a minute; a test at gigabit speed uses roughly 130. Past that, requests are refused for the rest of the minute and the result comes out low, so wait a minute and run it again.

Does the test keep or share my results?

No. The figures are worked out in your browser and stay on this page; the test sends them nowhere. The data it moves is random: downloads are generated as they stream and uploads are read and thrown away, so nothing you send is stored. To see the address and network the test ran from, use What’s my IP.

More network tools: What’s my IP, ASN lookup and the reverse DNS check.