Last updated: 27 September 2026
Short answer: work through it in order. First find out whether the problem is your internet connection or your Wi-Fi, by comparing a wired speed test with a wireless one. Then check whether it affects one device or all of them, measure the signal where it is slow, and check which band you are on. Most slow Wi-Fi comes down to distance and obstacles, interference on the 2.4 GHz band, or something else on the network using the bandwidth. A new router is the last step, not the first.
Why troubleshoot in a fixed order?
Because each step rules out a whole group of causes. Restarting the router, moving it and buying a new one are all reasonable fixes, but only for particular problems. Testing in order means you fix the actual cause and do not spend money on the wrong one.
Step 1: Is it the Wi-Fi or the internet connection?
Run a speed test in a browser twice:
- On a computer plugged into the router with a network cable, if you can.
- On Wi-Fi, standing next to the router.
Compare both with the speed your internet provider sells you.
- Wired test is slow too: the problem is the internet connection or the provider, not your Wi-Fi. Restart the modem and router, then contact your provider with the wired results.
- Wired is fine, Wi-Fi next to the router is fine, Wi-Fi elsewhere is slow: it is a coverage problem. Carry on with steps 3 to 6.
- Wired is fine, Wi-Fi is slow even next to the router: suspect the router's settings or firmware, interference, or the device itself.
Step 2: Is it one device or every device?
If only one laptop or phone is slow, the problem is probably that device: an old Wi-Fi adapter, outdated drivers, a VPN, or a background download. Restart it, update it, and forget and rejoin the network. A slow computer can also make everything, including browsing, feel slow; if that sounds familiar, see how to speed up an old Windows PC without buying anything.
If every device is slow in the same place, the problem is the network or the location.
Step 3: How strong is the signal where it is slow?
Signal strength is measured in dBm, a negative number where closer to zero is stronger. You can check it without extra apps:
- Windows: open Command Prompt and run
netsh wlan show interfaces. Look at Signal (a percentage), Band, Channel and Receive rate. - Mac: hold the Option key and click the Wi-Fi icon in the menu bar. It shows RSSI in dBm and the Tx Rate.
| Signal (dBm) | What it means in practice |
|---|---|
| −30 to −50 | Excellent; you are close to the router |
| −50 to −60 | Very good; fine for anything |
| −60 to −67 | Good; the usual target for reliable video calls |
| −67 to −70 | Fair; browsing and email work, calls may suffer |
| −70 to −80 | Weak; expect slowdowns and drops |
| Below −80 | Unreliable |
These bands follow common industry guidance, such as MetaGeek's explanation of RSSI. Exact figures vary slightly between devices, so compare readings on the same device in different rooms.
If the signal is weak where you work, the fix is coverage: steps 4 and 5.
Step 4: Are you on the right band?
Most routers broadcast on more than one frequency band, and they behave very differently:
| Band | Range | Speed | Typical problem |
|---|---|---|---|
| 2.4 GHz | Longest, passes walls best | Slowest | Crowded, and shared with microwaves, Bluetooth and neighbours' networks |
| 5 GHz | Medium | Fast | Weakens more through walls and floors |
| 6 GHz (Wi-Fi 6E and 7) | Shortest | Fastest, least crowded | Needs newer devices and a clear path |
A device clinging to 2.4 GHz near the router will be slower than it should be. Many routers combine bands under one network name and choose automatically, which usually works, but if a nearby device keeps landing on 2.4 GHz, giving the 5 GHz band its own name and joining it directly is a quick test.
In apartment buildings, 2.4 GHz is often crowded with neighbouring networks. Moving to 5 GHz or 6 GHz, or letting the router pick a less congested channel, can make a big difference.
Step 5: Is the router in the wrong place?
Placement is the most underrated fix. Wi-Fi signals weaken with distance and through walls, floors, metal and water, including fish tanks and radiators.
- Put the router central to where you use the internet, not at one end of the house where the cable happens to arrive.
- Raise it off the floor, onto a shelf or desk.
- Keep it out of cupboards and away from metal, televisions and the microwave.
- Point external antennas in a mix of vertical and horizontal positions if it has them.
Re-measure the signal after each change. Moving a router a couple of metres can move the dBm reading more than you would expect.
Step 6: Is something else using the bandwidth?
A connection can look slow simply because another device is busy. Common culprits are large cloud backups and syncs, game and system updates, and several 4K streams at once. The first cloud backup, in particular, can saturate a home upload for a day or more; I explained why in my 30-minute backup setup.
Most routers have an app or web page listing connected devices and their usage. If one device is hogging the connection, schedule its big transfers for overnight.
Step 7: Does the router need an update or a restart?
Restart the router, then check for firmware updates in its app or web interface. Firmware updates fix bugs and security holes, and sometimes performance problems. If your router is more than five or six years old and uses Wi-Fi 4 or Wi-Fi 5, it may simply be past its best.
Step 8: When is new hardware worth it?
Only after the steps above, and only for the problem you found:
- Large home or thick walls: a mesh Wi-Fi system with several units, ideally connected to each other by cable, fixes coverage better than one powerful router.
- Crowded apartment or many devices: a newer router with 6 GHz support helps, if your devices support it too.
- Wi-Fi 7: the Wi-Fi Alliance launched Wi-Fi CERTIFIED 7 in January 2024, bringing 320 MHz channels in the 6 GHz band and Multi-Link Operation, which uses several bands at once. It is worth buying if you are replacing a router anyway and your newest devices support it; it will not fix a weak signal caused by walls.
- A desk that never moves: a network cable is still faster and more reliable than any Wi-Fi.
FAQ
Why is my Wi-Fi slow only in one room?
Usually distance and obstacles between that room and the router. Measure the signal there. If it is weaker than about −70 dBm, move the router, add a mesh unit or run a cable.
Does restarting the router actually help?
Sometimes, because it clears temporary faults and can move the router to a less busy channel. If you need to restart it often, look for a firmware update or a failing router.
Should I use 2.4 GHz or 5 GHz?
Use 5 GHz, or 6 GHz if available, when you are reasonably close to the router, because it is much faster and less crowded. Use 2.4 GHz for devices far away or behind several walls, and for smart-home gadgets that only support it.
Will a Wi-Fi extender fix slow Wi-Fi?
It can extend coverage, but a basic extender often halves the speed it passes on. A mesh system, or an access point connected by cable, usually works better.
