Slow or patchy Wi-Fi at home? A step-by-step way to find the real cause

"The Wi-Fi is slow" is the most common complaint in any home. The trouble is that it can mean five different problems, and buying a new router only fixes one of them. Work through these steps in order and you will usually find the real cause in half an hour.

Step 1: Is it the Wi-Fi or the internet?

Plug a laptop into the router with a network cable and run a speed test. Then do the same over Wi-Fi standing next to the router.

• If both are slow, the problem is the internet connection or the router itself. Restart the router, check for outages with your provider and compare the result with the speed you pay for.
• If the cable is fast but Wi-Fi is slow even next to the router, look at the router's wireless settings or its age.
• If Wi-Fi is fast near the router but slow in other rooms, it is a coverage problem. Keep reading.

The bandwidth calculator helps you work out how long a download should take at your plan's speed, so you know whether what you see is really slow.

Step 2: Check where the router lives

Radio waves don't like walls, floors, mirrors, fish tanks or metal cabinets. A router hidden in a cupboard at one end of the house, behind the TV or on the floor will struggle. Move it somewhere central and high, out in the open. This free change often makes more difference than any new equipment.

Step 3: Understand the two bands

Most routers broadcast on 2.4 GHz and 5 GHz, and newer ones also use 6 GHz.

A phone at the far end of the house may cling to a weak 5 GHz signal when 2.4 GHz would be steadier. Some routers let you give the bands separate names so you can test each one. The Wi-Fi basics note explains bands and standards in more detail.

Step 4: Look at the channel

In flats and busy streets, dozens of networks share the same airwaves. Use a free Wi-Fi analyser app on a phone or laptop to see which channels your neighbours use. On 2.4 GHz, only channels 1, 6 and 11 don't overlap, so pick the least crowded of those. On 5 GHz there is more room, and the router's automatic choice is usually fine, but it is worth checking.

Step 5: Is it one device?

If one laptop is slow and everything else is fine, the router is not the problem. Check that device: update its Wi-Fi driver, forget the network and rejoin, and look for background downloads or cloud backups using all the bandwidth. On Windows, netsh wlan show interfaces shows the signal strength and the speed the laptop has agreed with the router. More useful commands are in essential network commands.

Step 6: Is it the time of day?

If everything slows down every evening, the cause may be your provider's network being busy, or simply everyone at home streaming at once. Run the cable test again at a quiet time and a busy time. If the cable result drops in the evening too, the problem is outside your house, and you have the evidence to give your provider.

Step 7: Extend coverage properly

If the house is simply too big for one router, you have three good options:

• Mesh Wi-Fi: several units that work as one network. Easy and effective.
• A wired access point: a second access point connected by a network cable. The most reliable choice if you can run a cable.
• Powerline adapters with Wi-Fi: use the house wiring to carry the network. Results vary with the age of the wiring.

Avoid cheap plug-in repeaters placed where the signal is already weak; they can only repeat a poor signal, and often halve the speed in the process.

While you are there: basic security

Update the router's firmware, change the default admin password, use WPA3 (or WPA2 if older devices need it), and put smart TVs and gadgets on a guest network if your router supports one. It keeps them apart from your laptops and phones.

Tip: write down what you changed and the speed test result after each step. It is exactly the habit you will need on a real network, and our "no internet" playbook follows the same method at work.