What the numbers mean
- Download — how fast data reaches you: websites, video, files.
- Upload — how fast you send: your camera in a video call, files to the cloud, backups.
- Ping — the round trip time to the server and back. For calls and games it matters more than speed.
- Jitter — how much the ping varies from packet to packet. High jitter makes voice sound robotic on calls.
- Loaded ping — the ping while the line is busy downloading or uploading. If it is much higher than the idle ping, that is bufferbloat: calls suffer as soon as someone on the network starts a download.
How much VoIP needs
A single call needs very little bandwidth; what matters is getting voice there on time. Bandwidth per call in each direction, including IP/UDP/RTP and Ethernet headers, with 20 ms packets:
| Codec | kbps |
|---|---|
| G.711 (PCMA/PCMU) | 87.2 |
| G.722 | 87.2 |
| Opus (typical) | 40–70 |
| G.729 | 31.2 |
For good quality, one-way latency should stay under 150 ms, jitter under 30 ms and loss under 1%. If calls already sound bad, load a traffic capture into our pcap analyzer: it shows MOS, loss and jitter for every call.
Cloudflare or M-Lab
Cloudflare uses anycast: your ISP's routing decides which of its nodes the test reaches. Sometimes it is the next city, sometimes another continent: many Middle East ISPs route this traffic to Europe. M-Lab first finds the server nearest to your location and tests to it. The M-Lab test runs over a single TCP connection for 10 seconds each way; Cloudflare makes a series of growing requests. If the two results differ a lot, the bottleneck is the route to that server, not your line.
Why the result is below your plan
Wi-Fi often costs more speed than the ISP does: for an honest result, plug in a cable. Pause downloads and streaming on other devices and turn off any VPN. Plans are usually sold as “up to”: that is the maximum to the ISP, not to every server on the internet.
The test uses data: up to a few hundred megabytes on a fast line. Mind your limits on mobile data.