How Wi-Fi works, and how to make yours better

Radio, but for data

Wi-Fi is a way for devices to talk to each other using radio waves, the same basic idea as a car radio or a baby monitor. Instead of music or voices, it carries data.

At the centre is your router, which acts as a small radio station for your home (see Router vs modem). It broadcasts a network name, and devices that know the password can join. Each device then sends and receives data with the router, which passes it on to the internet.

Think of the router as someone standing in the middle of a room, holding conversations with everyone in turn, very quickly. The more people talking, and the further away they stand, the harder it gets.

Bands and channels

Wi-Fi uses a few ranges of radio frequency, called bands. The common ones are 2.4 GHz and 5 GHz, and newer routers also use 6 GHz.

Each band is split into channels, like lanes on a road. If your neighbours' routers use the same lane as yours, everyone slows down. Most modern routers pick a quiet channel automatically.

Many routers show one network name and quietly move each device to the best band. Others show two names, one for each band. If yours does, use the 5 GHz one in rooms near the router and the 2.4 GHz one further away.

You may also see version names such as Wi-Fi 5, Wi-Fi 6, Wi-Fi 6E and Wi-Fi 7. Newer versions are faster and cope better with many devices, but only if both the router and the device support them.

What weakens the signal

• Distance. Signal fades quickly as you move away from the router.
• Walls and floors. Brick, concrete and especially metal block radio waves. Mirrors, fish tanks and radiators also get in the way.
• Interference. Microwave ovens, some cordless phones and baby monitors use similar frequencies.
• Crowding. Every device shares the same airtime. A games console downloading an update can slow everyone else.

Remember too that Wi-Fi is only the link inside your home. If your broadband itself is slow, a better Wi-Fi signal will not fix that. You can estimate what your connection can handle with the bandwidth calculator.

Make your Wi-Fi better: try this

1. Move the router. Put it high up, in the open, near the middle of the home. Not in a cupboard, behind the TV or on the floor.
2. Restart it occasionally. This clears glitches and lets it choose a fresh channel.
3. Use a cable for fixed devices. A TV, games console or desktop computer near the router works better plugged in, and frees up airtime for everyone else.
4. Add mesh points for large homes. A mesh system uses several small units that work together as one network, so the signal reaches every room.
5. Be wary of cheap plug-in extenders. They can help, but often halve the speed and create a second network name to switch between.

Keeping your Wi-Fi private

Because Wi-Fi travels through the air, anyone nearby can pick up the signal. Security settings make sure they cannot read it or use it.

• Use WPA3 security if your router offers it, or WPA2 otherwise. Avoid anything labelled WEP or "open".
• Choose a long Wi-Fi password, ideally a few random words together. Do not use your address or phone number.
• Change the router's admin password too. That one controls the settings, and is different from the Wi-Fi password.
• Use a guest network for visitors and smart gadgets, if your router has one. It keeps them separate from your own computers.

Tip: On public Wi-Fi in cafes, hotels and airports, stick to sites with the padlock, avoid online banking if you can use mobile data instead, and consider a VPN. See How a VPN works.

Want the technical version? See Wi-Fi basics.