A Wi-Fi speed test takes about twenty seconds, which is why most people run one, look at the number and stop. The number on its own is not much use. A test beside the router measures your broadband more than your Wi-Fi, and the rooms that give you trouble are rarely beside the router.
Testing properly takes a few minutes and a few rooms. Here is how, and what the results mean for the things you actually do in the house.
Why one test tells you very little
A speed test times data travelling between your device and a server. Everything on the way counts: your provider's network, the line into the house, the router, and the Wi-Fi between the router and you. Beside the router, the Wi-Fi part is short, so the result is mostly your broadband. Two floors up, the Wi-Fi part is the longest and hardest part of the trip.
So the useful information is not one number. It is the difference between the number at the router and the number in each room.
Before you start
- Use the same device for every test, ideally the phone or laptop you use most.
- Close anything downloading in the background: updates, cloud photo backups, a TV streaming in another room.
- Turn off a VPN if you use one, since it sends everything through another server first.
- Note the time. Results are often lower in the evening, when more people nearby are online.
Where to test
- Beside the router, or plugged into it by cable if you can. This is your baseline: what the broadband delivers before the Wi-Fi has to travel.
- In the room that struggles. Stand where you actually use the device: the desk, the bed, the couch facing the TV.
- Somewhere in between, such as the landing or the hall. It shows where the signal starts to fall away.
- Outside the front door, if you have a doorbell or a camera there. It sits on the far side of an outside wall, one of the hardest places in a house for Wi-Fi to reach.
What the numbers mean in your house
- Download, for the TV: Netflix recommends 15 Mbps for each 4K stream. Look at the figure in the room the TV is in, not the one beside the router.
- Upload, for cameras and calls: Ring asks for 2 Mbps of upload for each 1080p camera, and rates upload above 10 Mbps as good, 5 to 10 Mbps as okay, and below 5 Mbps as poor. Many broadband packages have far less upload than download to begin with, and the Wi-Fi can cut it further.
- Ping, for calls and games: how quickly the connection answers. Watch how it behaves while someone else is streaming: a connection that is quick when idle and stalls when busy is the one that breaks up video calls.
- How much each room keeps: our free check treats a room that keeps at least 60 per cent of the router's speed as fine, and one that keeps under 30 per cent as a room that has lost most of it.
Four patterns, and what each points to
Slow everywhere, including beside the router. The broadband itself. Test on a cable at the router at two different times, then take the figures to your provider. Our guide to telling the line from the Wi-Fi goes through it step by step.
Fast at the router, slow upstairs or at the back of the house. The Wi-Fi is not getting through the house. Walls, floors, foil-backed insulation and distance are taking it on the way.
Fine in the daytime, slow in the evening, even at the router. Congestion on the line or on your provider's network at busy times. Another case for your provider, with the evening figures.
Download fine, upload poor. Cameras, doorbells and video calls suffer first. Check the upload on your contract, then check it in the room or at the door where the camera is.
Doing it with the free check
Our free Wi-Fi check does this in order: a test beside the router, a test in the room that struggles, six questions about your home, and a report graded green, amber or red with what to do next. The speed test itself is run by Measurement Lab, the same open platform behind Google's speed test, and the check tells you before you start that Measurement Lab publishes each result with the internet address it came from.
If the report comes back amber or red, the €395 home network assessment is the next step: your broadband tested at the router by cable, every floor measured, and a working trial system left on the floor that struggles for three days, with the figures in writing. It is credited in full against any work you go ahead with.