Short answerTest from a laptop plugged into the router by cable, record download, upload and latency together with the router’s RSRP and SINR, and repeat at busy and quiet times. Compare networks using the same method at the same spot.
Years ago this page reported a single 4G result from an office on the edge of coverage: 10Mbps down, 2Mbps up, but rock steady for a month. That last point is still the lesson. Consistency at the times you need it matters more than a headline peak.
A method that works
- Use a cable. Wi-Fi adds its own limits. Plug a laptop into the router, or use the router’s built-in speed test if it has one.
- Note the signal first. Write down RSRP, RSRQ, SINR and the band from the router’s status page. Our signal guide explains them.
- Test three things. Download, upload and latency (ping). For CCTV and video calls, upload and latency matter more than download.
- Repeat at different times. Early morning, lunchtime and early evening show how busy the cell gets.
- Use the same server. Pick a nearby UK test server and stick with it, so results are comparable.
- Compare networks properly. Same router, same position, same times, one SIM after another.
What good looks like
There is no single target, because it depends on the job. Some practical yardsticks:
| Use | What matters |
|---|---|
| Payments, alarms, telemetry | Stable connection and low latency, not speed |
| Video calls | Steady upload of a few Mbps and consistent latency |
| Remote CCTV viewing | Upload, especially for several cameras |
| Office internet | Download and upload at the busiest hour, not the quietest |
Reading the results
- Fast early, slow in the evening: the cell is congested. Another network or a different band may be quieter.
- Slow all day with poor SINR: a signal problem. See antennas.
- Good download, very poor upload: typical of a weak signal, because the router has to transmit back to the mast.
- Latency jumps around: often a sign of a marginal signal or a very busy cell.
Surveying a site
For installers, a dedicated signal analyser measures all networks at once and saves a lot of SIM swapping. Our old post on the CSL signal analyser shows what they report.
Frequently asked questions
What is a good 4G speed?
It depends on the use. A steady few Mbps is plenty for payments and telemetry, while an office of ten people will want tens of Mbps at its busiest hour.
Why do speed tests vary so much?
Other users share the cell, the router may change band, and conditions vary through the day. That is why you should test several times.
Should I test on a phone?
A phone gives a rough idea, but its antennas and position differ from the router’s. Test with the router where it will be installed.
NANick Appleby
Nick Appleby has worked in UK telecoms since 1998, starting at BT, and has spent most of that time on cellular routers, data SIMs and the antennas that connect them for business and industrial sites. He writes 4G SIM to explain how the networks and the kit actually behave, in plain English.