Why Your Computer Internet Is Slow and How to Fix It

The most common reasons your internet slows down

Slow internet usually comes from one of three places: your internet service provider (ISP) is delivering less speed than you pay for, something on your network is eating bandwidth, or your computer itself has a problem. Most people assume the ISP is at fault, but the issue is often sitting in your own home.

Start by testing your actual speed. Go to speedtest.net or fast.com on any device connected to your network and run the test. Write down the read speed, upload speed, and ping. Then check your bill or your ISP's website to see what speed you actually pay for. If the test shows you are getting 80 percent or more of your advertised speed, your ISP is delivering what it promised — the slowness is happening elsewhere.

If the test shows much lower speeds, restart your modem and router. Unplug both for 30 seconds, plug in the modem first, wait for all lights to stabilize, then plug in the router and wait again. Run the speed test a second time. Many speed problems vanish after a restart because the modem or router has filled its memory buffer or lost its connection to the ISP.

Key Takeaways

Run a speed test at speedtest.net to see what your computer is actually receiving, then compare it to what your bill says you pay for.
Restart your modem and router by unplugging both for 30 seconds — this fixes most temporary slowness without any other work.
Check how many devices are using your network at the same time, because streaming video, downloads, or cloud backups on other devices will slow your computer's internet.
Malware, browser extensions, and too many browser tabs can make your computer feel slow even when your internet speed is fine.
If your computer is slow only on Wi-Fi but fast when plugged in with ethernet, the problem is your wireless connection, not your internet service.

Too many devices or programs using your bandwidth

Your internet speed is shared among every device on your network. If someone is streaming video, downloading a large file, or running a cloud backup on another computer or phone, your computer's internet will slow down. Check what else is connected and what it is doing.

On Windows, open Task Manager (press Ctrl+Shift+Esc), click the Performance tab, then click Open Resource Monitor. Click the Network tab and look at the Processes with Network Activity section. You will see which programs on your computer are sending or receiving data. Close any you do not recognize or do not need running right now.

On Mac, open Activity Monitor (search for it in Spotlight), click the Network tab, and look at the Sent and Received columns. Programs with high numbers are using your bandwidth. Quit the ones you do not need.

If your computer shows no heavy network use but the internet still feels slow, check your other devices. Ask anyone else in your home if they are streaming, downloading, or video calling. If they are, that is your answer — wait for them to finish, or ask them to pause while you need the speed.

Wi-Fi problems versus internet service problems

If your computer is slow on Wi-Fi but fast when you plug in an ethernet cable, your internet service is fine — your wireless connection is the problem. If it is slow both ways, the issue is your internet service or your modem.

To test with ethernet, plug a cable directly from your modem into your computer's ethernet port (you may need an adapter if your computer does not have one). Run the speed test again. If the speed jumps up, your Wi-Fi is weak or congested.

Wi-Fi slowness usually happens because your router is too far away, blocked by walls, or competing with other Wi-Fi networks in your building. Move your router to a central, high location away from metal objects and microwaves. If that does not help, restart the router. If the problem persists, your router may be old or failing — routers typically last three to five years before performance drops.

Malware and browser problems that feel like slow internet

Malware, unwanted browser extensions, and too many open tabs can make your computer slow without actually slowing your internet. Your internet speed test will show normal numbers, but browsing will feel sluggish.

Run a malware scan using Windows Defender (built into Windows) or Malwarebytes (free version available). On Windows, open Windows Security, click Virus and threat protection, and run a Quick scan. On Mac, use Malwarebytes or your built-in XProtect by going to System Settings, Privacy and Security, and checking the Security section.

Check your browser extensions. In Chrome, click the three dots in the top right, go to Extensions, and disable any you do not recognize or use regularly. In Firefox, click the menu button, select Add-ons, and disable suspicious extensions. In Safari, go to Safari menu, Preferences, Extensions, and uncheck extensions you do not need.

Close unused browser tabs and restart your browser. Each open tab uses memory and can slow your computer's performance, making internet feel slow even when it is not.

Your modem or router needs replacement

Modems and routers wear out. If your modem is more than five years old, it may not support the speeds your ISP is sending. If your router is more than three years old, its wireless performance may have degraded.

Check the age of your modem by looking at the sticker on the back or calling your ISP — they have a record of when it was installed. If it is old, ask your ISP whether they will replace it for free. Many ISPs provide modems at no cost or will swap an aging one.

For routers, check the model number on the sticker. Search the model online to see when it was released. If it is old, a newer router will usually improve Wi-Fi speed and range. You do not need an expensive one — a mid-range router from a major brand (TP-Link, ASUS, Netgear) will work well for most homes.

Your ISP is not delivering the speed you pay for

If your speed test shows you are getting less than 80 percent of your advertised speed, and you have restarted your modem and router, the problem is likely your ISP.

Run the speed test three times at different times of day and save the results. ISPs often slow down during peak hours (evening and night), so testing at 2 p.m. and 8 p.m. will show whether that is happening. If you are consistently getting much lower speeds, contact your ISP and tell them your test results. Ask them to check your line for problems. Many ISPs will send a technician to test the connection at no cost if you are not getting what you pay for.

If the technician finds no problem on their end, ask whether your plan is still available or whether your ISP has upgraded the area to faster speeds. Sometimes plans are discontinued and you are grandfathered into an older, slower tier. Switching to a current plan may give you better speed at the same price.

DNS and network settings that slow you down

Your computer uses a Domain Name System (DNS) server to translate website addresses into numbers it can understand. If your DNS server is slow or far away, websites will load slowly even though your internet speed is fine.

Try changing your DNS to a faster public one. On Windows, right-click the network icon in the system tray, click Network and Internet settings, then Ethernet or Wi-Fi, then Change adapter options. Right-click your connection, select Properties, find Internet Protocol Version 4 (TCP/IPv4), click Properties, and change the DNS servers to 8.8.8.8 and 8.8.4.4 (Google's DNS). On Mac, go to System Settings, Network, Wi-Fi or Ethernet, Details, DNS, and add those same addresses.

Restart your browser and test a few websites. If they load faster, the DNS change helped. If not, change it back and try a different approach.

Frequently Asked Questions

How do I know if my internet is actually slow or if it just feels slow?

Run a speed test at speedtest.net and compare the result to your bill. If you are getting 80 percent or more of what you pay for, your internet is working as promised. If websites still load slowly, the problem is your computer, browser, or Wi-Fi, not your internet service.

Why is my internet fast on my phone but slow on my computer?

Your phone and computer are on the same network, so the internet service is the same. The slowness is on your computer — check for malware, too many browser tabs, or heavy programs running in the background. If your phone is also slow, restart your modem and router.

Does restarting my modem and router really fix slow internet?

Yes, often. Modems and routers fill their memory buffers and can slow down until they are restarted. Unplug both for 30 seconds, plug the modem in first, wait for it to stabilize, then plug in the router. This fixes most temporary slowness.

What is a good internet speed?

For one person browsing and streaming, 25 Mbps is usually enough. For a household with multiple people streaming or video calling at the same time, 100 Mbps or higher is better. Check what you pay for on your bill and compare it to your speed test result.

Should I buy a new router if my internet is slow?

Only if your speed test shows you are getting the full speed your ISP promises and your computer is fast when plugged in with ethernet. If the ethernet test is also slow, your ISP is the problem, not your router. If ethernet is fast but Wi-Fi is slow, a new router will help.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.