Does the microwave interfere with Wi-Fi? How to check, and what to do
It sounds like a myth, but it isn't: a running microwave oven can disturb Wi-Fi nearby. Only on one band, only while it runs, and it's easy to confirm.
In short
- A microwave oven heats with radio energy at about 2.45 GHz, inside the 2.4 GHz Wi-Fi band. A tiny leak of that power is still strong next to a Wi-Fi signal.
- The effect is local, temporary and on 2.4 GHz only: near the kitchen, while the oven runs. 5 GHz isn't affected.
- To confirm it, compare a device on 2.4 GHz and then on 5 GHz near the kitchen while heating a cup of water.
- Fixes: keep the router out of the kitchen, put nearby devices on 5 GHz. If the oven disturbs Wi-Fi across several rooms, have the door seal checked.
On this page
Some people notice a pattern: the Wi-Fi in or near the kitchen goes bad for exactly as long as the microwave is running, and comes back the moment it stops. It sounds like an urban legend. It isn't, and the reason is simple.
Why it happens
A microwave oven heats food with radio waves at about 2.45 GHz. That frequency sits inside the 2.4 GHz band that Wi-Fi uses, which runs from roughly 2.4 to 2.48 GHz. The oven works at hundreds of watts, while a Wi-Fi router transmits at a fraction of a watt.
The metal box and the mesh in the door keep almost all of the oven's energy inside. But "almost all" of hundreds of watts is still a lot compared with a Wi-Fi signal that has crossed a couple of rooms. Devices on 2.4 GHz near the oven hear it as noise, wait for the channel to clear, resend data, and slow down.
What it does and doesn't affect
The effect is narrow, and that's what makes it easy to recognise.
- Only 2.4 GHz. The oven's energy is nowhere near 5 GHz or 6 GHz. Devices on those bands don't notice it.
- Only nearby. It fades quickly with distance and walls. The kitchen and the room next to it may suffer; the other end of the home won't.
- Only while it runs. The moment the oven stops, the connection returns to normal.
If the whole home slows down at random times, the microwave isn't the cause. Look at full bars but slow Wi-Fi instead.
Confirm it in one minute
Put a cup of water in the microwave and set it for a minute. While it runs, play a video or run a speed test on a phone or laptop near the kitchen, connected to 2.4 GHz. Then repeat with the device connected to 5 GHz.
If the 2.4 GHz connection stalls only while the oven runs and the 5 GHz one doesn't, the microwave is the cause. If both are poor whether the oven is on or off, the kitchen has a different problem: its walls, tiles and appliances block the signal. See what blocks Wi-Fi at home.
If your router uses one name for both bands, you may need to separate them briefly to choose the band for the test; 2.4 or 5 GHz explains how.
What to do about it
Keep the router out of the kitchen, and away from the wall the oven stands against. Routers often end up there because the line or a free socket is nearby.
Put the devices near the kitchen on 5 GHz if they support it: the laptop on the kitchen table, the tablet for recipes. They become immune.
Mind the line between router and device. A device that receives the router through the oven gets both the interference and the obstacle of a metal box.
Smart devices are the usual victims. Many plugs, speakers and displays work only on 2.4 GHz. If one in the kitchen drops out whenever the oven runs, move it a little further from the oven or out of its line to the router.
When it's worth checking the oven
Some disturbance close to a running oven is normal. If yours knocks out Wi-Fi in several rooms, or the effect has grown over time, the door seal may be worn or the door may not close properly. That reduces the shielding, and it's worth having the oven checked by a technician rather than testing it yourself.