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Why Wi-Fi slows down
What eats into your Wi-Fi speed, and why moving closer or changing band helps.
The short version
Wi-Fi slows down for four reasons: you are far from the router, there are walls in the way, other networks are using the same channel, or many devices are sharing the airtime. It builds on how Wi-Fi works.
I always blamed my broadband when the video buffered.
The cable was usually fine.
The slow part was the last few metres, through the air.
Four things that slow it
Distance. The signal weakens as it spreads. A weak signal forces your device and router to use simpler, slower ways of sending data.
Walls and floors. Brick, concrete, mirrors, water tanks and metal absorb or reflect radio waves. Two walls can matter more than ten metres of open room.
Crowded channels. Each band is divided into channels. Nearby networks using the same channel share airtime and may have to wait or retransmit when signals collide.
Sharing. Only one device can transmit on a channel at a time. A device that is far away sends slowly and so takes longer on the air, which holds up everyone else.
What to try
Move closer, or move the router somewhere central and higher up, not behind the television. For devices that stay put, such as a TV, an Ethernet cable avoids Wi-Fi altogether. Some routers let you choose a less crowded channel. A device that supports the 5 GHz band will often be faster near the router; 2.4 GHz may be better two rooms away.
Key takeaways
- A slow video is often the Wi-Fi, not the broadband.
- Distance and walls weaken the signal.
- Neighbours' networks can crowd the same channels.
- Devices take turns on the air.
- Closer, higher, or a cable for fixed devices all help.
Now you know.
Slow video is often the air, not the cable.
Walls and neighbours weaken and crowd the signal.
A cable beats radio for anything that stays still.
Last reviewed 3 Nov 2026
