Why is my internet so slow? A step-by-step check

If you are asking "why is my internet slow?", the cause is usually one of four things: a single device, your Wi-Fi signal, your router or your provider's line. The quickest way to find out is to check them in that order, using a speed test at each step. Most problems can be pinned down in fifteen minutes.

Why is my internet slow? Start with three quick questions

Before testing anything, answer these. They point you to the right part of the chain.

1. Is it slow on every device, or just one? If only one phone or laptop is slow, the problem is probably that device.
2. Is it slow everywhere in the home, or only in some rooms? If only far rooms are slow, it is probably Wi-Fi coverage.
3. Is it slow all the time, or only at certain hours? If evenings are bad and mornings are fine, congestion is likely.

Step 1: Check the device

1. Restart it. This clears stuck apps and resets the network connection.
2. Close background apps and pause downloads, updates and cloud backups.
3. Turn off any VPN and test again.
4. Check battery saver and data saver. On most phones, search Settings for "Battery saver" and "Data saver".
5. Forget and rejoin the Wi-Fi network if the connection still feels stuck.

If the device is now fast, you have your answer.

Step 2: Check the Wi-Fi signal

1. Move next to the router and run a speed test.
2. Run the same test in the room where it was slow.
3. Note the Wi-Fi signal in dBm in both places. Around −67 dBm or stronger is generally fine; below about −75 dBm, expect trouble.

If the test is fast near the router and slow in the far room, Wi-Fi coverage is your problem. How to find and fix Wi-Fi dead zones covers the fixes, from moving the router to adding a mesh unit.

If it is slow even next to the router, move on.

Step 3: Check for a crowded channel or band

If the signal is strong but speed is poor, especially in the evening:

• check whether you are on 2.4 GHz near the router; 5 GHz is usually faster close up
• check the channel for strong neighbouring networks
• try a quieter channel in your router's settings

Step 4: Restart the router

Routers can slow down after running for a long time. Turn the router off at the wall, wait about 30 seconds and turn it on again. Give it a few minutes to reconnect fully, then test again.

While you wait, look at the router's lights. A red or orange light on the internet or broadband indicator often means a problem with the line.

Step 5: Test the line directly

If you can, connect a laptop to the router with a network cable and run a speed test. This removes Wi-Fi from the picture. For a fair result, follow how to run an internet speed test that tells the truth.

• Cable result close to your plan: the line is fine. The slowdown is in your Wi-Fi or devices.
• Cable result well below your plan: the problem is likely the router, the line or your provider.

Step 6: Check what else is using the connection

One device can slow down everyone else. Look for:

• a games console or PC downloading a large update
• a computer backing up photos or files to the cloud, which can fill your upload
• several people streaming in high quality at once
• an unknown device on your Wi-Fi

Your router's app or settings page may show which devices are connected and how much they are using.

Step 7: Check your provider

1. Look for outages. Your provider's website, app or status page often lists known problems in your area.
2. Test at different times and keep notes. If speeds are always low in the evening, that is congestion on their network.
3. Check your plan. Some plans slow you down after a usage limit, and older plans may simply be slower than you remember.

If the cable test is slow at all hours and there is no outage, contact your provider. When to call your internet provider explains what to tell them so they can help faster.

When speed tests look fine but it still feels slow

Sometimes every test passes and pages still crawl. That usually means high delay, a slow DNS lookup or a problem with one particular service, rather than low speed. Fast speed test but slow apps covers this case.

How CellRadar helps

CellRadar has a Network Doctor that runs step-by-step checks and gives a plain-language verdict on why your internet is slow. The speed test measures download, upload, ping and jitter, the Wi-Fi Meter shows your signal in each room, and the Device Scanner lists the devices on your Wi-Fi. You can also type a question into Ask CellRadar and it runs the right test. It finds the cause; the fix is yours or your provider's to make.

Frequently asked questions

Why is my internet slow at night?

Evenings are the busiest time, both on your home Wi-Fi and on your provider's network. If speed drops only at night, congestion is the likely cause.

Why is my internet slow on one device only?

That device may have too many background apps, a VPN, a power-saving setting or an old Wi-Fi chip. Restart it and compare with another device in the same spot.

How often should I restart my router?

Only when you have a problem. A restart can clear temporary faults, but there is no need to do it on a schedule.

Can too many devices slow down my internet?

Yes, if several are using a lot of data at once. Smart home devices on their own use very little.