Why Is My Internet So Slow? 10 Causes and Fixes

When your internet is slow, the cause is usually one of a few things: weak Wi-Fi, too many devices using the line at once, a busy evening at your provider, a router that lets queues build up, or something on your own device such as a VPN or a background update. The fastest way to find which one is to test in a set order, starting with a speed test on a wired connection.

Step 1: Test wired, then on Wi-Fi

Plug a computer into the router with a cable and run the speed test. Then run it again on Wi-Fi in the room where things feel slow. This one comparison splits almost every problem in two.

• If wired is fast and Wi-Fi is slow, the problem is inside your home: the router, its position or interference. Go to causes 1 to 3.
• If both are slow, the problem is the line, the router itself or your provider. Go to causes 4 to 7.
• If speeds look fine but things still feel slow, look at latency and DNS. Go to causes 8 to 10.

1. Weak Wi-Fi signal

Wi-Fi speed falls quickly with distance, walls and floors. A router in a cupboard, behind a TV or at one end of the house leaves other rooms with a fraction of the real speed. Move the router to a central, open spot, raised off the floor. For a large home, a mesh system works better than a single router with a range extender, because extenders often halve the speed they repeat.

2. The wrong Wi-Fi band

The 2.4 GHz band reaches further but is slower and crowded. The 5 GHz band, and 6 GHz on newer routers, is much faster at shorter range. If your device sits near the router and still connects at 2.4 GHz, connect it to the 5 GHz network or give the bands separate names so you can choose.

3. Interference and crowded channels

In flats and apartments, many neighbouring networks compete for the same channels, and some household devices interfere on 2.4 GHz. Let the router pick a channel automatically after a restart, or choose a less crowded one in its settings. You can reach those settings through your router's IP address.

4. Too many devices at once

Every stream, call, game download and backup shares the same connection. A single 4K stream needs about 15 Mbps, and a console update can take everything that is left. Check what else is running when the internet feels slow, and schedule large updates and backups overnight. Our guide to what a good internet speed is helps you check whether your plan fits your household.

5. Lag when the line is busy (bufferbloat)

If browsing and calls fall apart only when someone else is downloading or uploading, the router is probably letting a queue build up. This is called bufferbloat. Our speed test measures latency during the download and upload and gives a grade. A C or worse is fixed by turning on Smart Queue Management (SQM) in the router, not by buying a faster plan.

6. An old router or modem that needs a restart

Routers run for months without a reboot and can slow down or drop connections. Restart the modem and router: unplug both, wait 30 seconds, plug the modem in first, then the router. If problems return often, or the router is several years old and lacks Wi-Fi 6, a newer one is likely to help more than a faster plan. Also check that its firmware is up to date.

7. Congestion or throttling at your provider

If a wired test is fast in the morning and slow every evening, your provider's network is likely congested at peak time. Some plans also slow down after a data cap. Record wired speed test results at different times of day for a few days, then contact your provider with them. The guide to finding your ISP helps if you are not sure who runs your line.

8. A VPN or proxy

A VPN sends all your traffic through its server, which adds distance and can cap your speed. Run the speed test with the VPN off and on. A large difference means the VPN server is the bottleneck, so try a closer server or a different protocol. Our guide to checking that a VPN works shows how to confirm it is still protecting you after the change.

9. Slow DNS

If pages take a moment to start loading but then load quickly, DNS may be the delay. Every new website name has to be looked up first, and a slow resolver adds that wait to each one. Switching to a fast public resolver often helps. See how to fix a slow DNS lookup.

10. Your own device

An old laptop, a phone in power-saving mode, a browser with dozens of tabs or a background cloud sync can all make the internet feel slow when the line is fine. Test another device in the same spot. If only one device is slow, the problem is that device: update it, close background apps, and check for a long-running download or update.

When to contact your provider

Call your provider when a wired speed test is well below your plan at several times of day, after you have restarted the modem and router. Give them the results with dates and times. A wired result is the evidence they cannot blame on your Wi-Fi.

Frequently asked questions

Why is my internet slow all of a sudden?

A sudden drop usually comes from something that just changed: a large update or backup starting on one device, a router that needs a restart, an outage or works in your area, or a new device crowding the network. Restart the router, check what is downloading, and run a wired speed test.

Why is my internet slow at night?

Evening is the busiest time on most residential networks, so a provider with too little capacity slows down then. If wired tests are consistently slower in the evening, report it to your provider with the results.

Why is my Wi-Fi slow but wired is fine?

The line is fine, so the limit is the wireless link: distance, walls, the 2.4 GHz band, interference or an older router. Move closer, switch to 5 GHz, or add a mesh system.

Sources and further reading

• Netflix Help Center: Internet connection speed recommendations