Why is my internet slow? A step-by-step way to find out

“The internet is slow” can mean a dozen different things. Pages crawl, video buffers, calls stutter, downloads stall. The trick is to work in order, from the thing closest to you outwards, so each test rules something out.

First: is it everything, or one site?

Open two or three unrelated sites. If only one is slow, the problem is probably that site or the route to it, not your connection. Paste it into our website checker to see how it responds from our server and from other countries. If it is quick for us and slow for you, keep reading. If it is slow for everyone, nothing you change at home will help, and it is worth looking at the outage map and the advice for when a service is down.

Second: is it one device, or all of them?

Try another phone or laptop on the same Wi-Fi. If only one device is slow, the cause is on that device: a browser that needs restarting, a full storage drive, a background update, a VPN or a security tool. Restart the device and the browser first, then try a private window to rule out extensions.

Third: is it the Wi-Fi?

Run our speed test standing next to the router, then again in the room where it is slow. A big drop means a Wi-Fi problem, not an internet problem. Common causes:

• Distance and walls. Thick walls, floors and mirrors weaken the signal, and the 5 GHz band is faster but travels less far than 2.4 GHz.
• Crowded channels. In flats, dozens of neighbouring networks compete for the same airspace. Choosing a different channel, or letting the router pick one automatically, can help.
• Interference. Microwaves, cordless phones and baby monitors can disturb 2.4 GHz.
• Too many devices. Many connected gadgets share the same bandwidth, and older ones can slow everyone down.

If you can, connect a laptop to the router with a cable and test again. A cable removes Wi-Fi from the picture completely.

Fourth: is it the router?

Routers run for months without a break and can slow down or develop faults. Restart yours: unplug it for thirty seconds, plug it back in and wait a few minutes. Check for a firmware update in its settings. If the router is many years old, it may simply not keep up with your plan. Our guide to telling a router fault from an internet provider fault goes deeper.

Fifth: is it your plan or your provider?

With a cable connection, a speed test far below what you pay for, at several different times of day, points at the provider or the line. Note the download speed, the upload speed and the ping, then compare them with your plan. Speeds that drop at busy evening hours suggest congestion in your area. A very high ping, or ping that jumps around, suggests a line or routing problem, which our guide to latency, packet loss and jitter explains.

Sixth: could something be using your bandwidth?

A device in the house downloading a large update, backing up photos, or streaming in high quality can use most of your connection, leaving little for everyone else. Pause big downloads and cloud backups and test again. Check that nobody on the network is running something heavy.

Seventh: could it be DNS?

If the first page of a site takes a long time to start but then loads fine, slow name lookups are a common cause. Trying a different public DNS resolver in your router or device settings sometimes makes browsing feel snappier. What DNS is and why it fails has the background.

What the numbers mean

• Download speed matters for streaming, browsing and large files.
• Upload speed matters for video calls, sending large files and cloud backups.
• Ping, or latency matters for gaming, calls and how responsive pages feel. Lower is better.
• Consistency often matters more than the peak number. A steady connection feels faster than a fast one that keeps stalling.

When to contact your provider

If you have tested with a cable, restarted the router, ruled out your devices and still see speeds well below your plan at several times of day, contact your provider. Having a few speed-test results with dates and times, and saying you tested on a cable, makes the conversation much faster.

Quick checklist

1. One site or all sites?
2. One device or all devices?
3. Test next to the router, then where it is slow.
4. Test on a cable if you can.
5. Restart the router and check for updates.
6. Pause large downloads and backups.
7. Test at different times of day and keep the results.

Related guides

• Is it my Wi-Fi, my router or my internet provider?
• Latency, packet loss and jitter explained
• What is a good website response time?

Last updated 2 November 2026. Written by the siteupdown.com team. Spotted a mistake?

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