What a speed test measures, and what it misses
A single number from a browser tab is a snapshot of one path at one moment. Read alongside two other figures, it becomes genuinely diagnostic.
By Jonas Kelleher · Devices & Testing
5 min readReported from Portland, OR
A speed test measures a transfer between one device and one test server, over whatever path happens to be available at that second, including the wireless hop inside the home. It is a real measurement. It is simply a narrower one than the headline figure suggests.
Three numbers, not one
Throughput answers how much can move at once. Latency answers how long a single exchange takes, which is what determines whether a video call feels natural. Jitter answers how much that delay varies, and a connection with respectable throughput and unstable jitter will still produce a call that stutters. Households troubleshooting a meeting problem usually need the second and third figures, not the first.
How to test in a way that tells you something
- Test from a wired device if one is available. This separates the service from the wireless network inside the home.
- Repeat the test at the hour the problem occurs, not only when you are investigating it.
- Run it three times and note the spread rather than the best result.
- Test from the room where the fault appears as well as from beside the router.
Kept as a short log over a week, these results describe a pattern, and a pattern is what a support conversation can actually act on. A single screenshot of a bad result rarely is.
What informed this article
- Published measurement methodology from public broadband measurement programmes — Referenced for latency and jitter definitions.
Jonas Kelleher
Devices & Testing
Jonas documents how we test routers and mesh systems, and translates lab measurements into what they mean in an ordinary apartment.
Corrections
If anything here is inaccurate or out of date, tell us and we will correct it and note the change on the article. Write to editorial@mywifiguide.com.
General information for a general audience. Not professional advice, and not a recommendation to buy any product or service.