Mobile hotspot
How to speed test a phone hotspot (without wasting your data)
Short answer: run one test from the laptop connected to the hotspot, not from the phone, because that is the path your work actually takes. Expect a single test to use roughly as many megabytes as your speed in Mbps multiplied by 1.25 for the download half, plus the same again for upload, so a 100 Mbps 5G hotspot can use well over 100 MB per test. Test once or twice, not ten times, and test again where you will actually sit.
How much data does one speed test use?
A speed test works by moving as much data as it can for a fixed time. Our test, like every ndt7 client, runs each direction for up to ten seconds over one connection (methodology). So the data used is roughly speed × 10 seconds ÷ 8 bits per byte, for each direction:
| Hotspot speed (down / up) | Download half | Upload half | One full test |
|---|---|---|---|
| 10 / 3 Mbps (weak 4G) | about 12.5 MB | about 4 MB | about 16 MB |
| 50 / 10 Mbps (good 4G) | about 62.5 MB | about 12.5 MB | about 75 MB |
| 150 / 20 Mbps (typical 5G) | about 190 MB | about 25 MB | about 215 MB |
| 400 / 40 Mbps (strong 5G) | about 500 MB | about 50 MB | about 550 MB |
This is in line with official figures: the FCC's own speed test app warns that a complete suite of tests can consume "between 100 kB for the smallest packet loss test and 600 MB for the fastest 5G networks" (FCC Measuring Broadband America, mobile). On a plan with 5 GB or 15 GB of hotspot data, three or four tests on a fast 5G cell can take a visible bite.
Why the laptop tests slower than the phone
- The phone-to-laptop link is Wi-Fi too. Phones often run their hotspot on 2.4 GHz for compatibility. Switching the hotspot to 5 GHz (on Android often called "AP band" or "Wi-Fi hotspot band"; on iPhone, "Maximize Compatibility" off) can raise the laptop's result substantially if the phone's mobile link is fast.
- USB tethering skips that Wi-Fi hop. A cable between phone and laptop removes radio interference and keeps the phone charged.
- Some plans treat hotspot traffic differently. Many mobile plans give tethered data a separate, smaller allowance and slow it down after that allowance is used, while the phone's own browsing keeps full speed. If the phone tests at 150 Mbps and the laptop at 3 Mbps, check your plan's hotspot terms before blaming the hardware.
- The phone gets hot. A phone in a sunny window or charging under a pillow can throttle its modem. Put it somewhere cool and open.
Where to put the phone
Mobile signal changes a lot over a few metres. Before you run the test, move the phone to a window facing the nearest mast or, failing that, to the highest floor. Then leave it there: a hotspot test is only useful for the place it was run. If you are choosing between two spots, run one test in each rather than five in one.
Is the hotspot fast enough for the job?
| Task | What the service recommends | Source |
|---|---|---|
| Zoom 1:1 video at 720p | 1.2 Mbps each way | Zoom |
| Microsoft Teams video meeting | 2.5 Mbps up / 4 Mbps down recommended | Microsoft |
| YouTube at 1080p | 5 Mbps sustained | YouTube Help |
| Netflix in HD (720p) | 3 Mbps or higher | Netflix Help |
For calls, latency matters as much as speed. Cellular links usually have higher and more variable latency than home broadband, and it climbs further when the laptop starts a large upload. Look at the latency under load figure in your result; if it rises by more than about 100 ms, pause cloud sync while you are on calls. Our latency guide explains why.
Save data while you work on a hotspot
- Mark the hotspot as a metered connection on the laptop (Windows and macOS both offer this) so updates and cloud sync wait.
- Pause photo and backup sync before you connect. See how much a backup uploads.
- Lower video call resolution to 720p. Zoom lists 3.8 Mbps upload for 1080p video against 2.6 Mbps for 720p group calls, about a third less data sent.
Related
What works on a very slow connection · Video call requirements compared · Streaming bandwidth calculator · Mbps to MB/s converter