Your speed is slow because something between your device and the internet is creating a bottleneck
Internet speed depends on three things working together: your connection to your modem, your modem's connection to your internet service provider, and how much of that connection your devices are actually using right now. When speed drops, one of those three is the problem. Most of the time it is not your ISP's fault — it is something in your home, something on your device, or straightforward too many things using the connection at once.
The speed you pay for — say, 100 megabits per second — is the maximum your line can carry. You almost never see that number in real life. A speed test showing 60 or 70 megabits when you pay for 100 is normal. A speed test showing 10 or 20 is a sign something is wrong.
Key Takeaways
- Run a speed test on a device plugged directly into your modem with ethernet cable to see what your ISP is actually delivering to your home.
- If the wired speed is close to what you pay for, the problem is your WiFi signal, your device, or too many things using the connection at once.
- If the wired speed is much lower than what you pay for, restart your modem by unplugging it for 30 seconds, then run the test again.
- WiFi speed drops when your device is far from the router, when other networks on the same channel are nearby, or when walls and metal objects are between you and the router.
- Background apps, browser extensions, and malware can slow a single device even when other devices on the network are fast.
Test your actual connection speed with a wired device first
Before you do anything else, you need to know whether the problem is your internet line or something in your home. The only way to know is to plug a computer directly into your modem with an ethernet cable and run a speed test. Go to speedtest.net or fast.com, run the test, and write down the number.
If that number is within 10 or 15 percent of what you pay for — so if you pay for 100 megabits, anything above 85 is fine — your ISP is delivering what it promised. The slowness is happening after that point. If the number is much lower, your modem or line has a problem.
Most people skip this step and test on WiFi instead, which tells you nothing useful because WiFi is always slower than the wired connection. You are testing your WiFi signal, not your internet speed.
Restart your modem if the wired speed is too low
A modem that has been running for weeks or months can get stuck in a state where it is not communicating properly with your ISP's equipment. Restarting it fixes this about half the time. Unplug the modem from power, wait 30 seconds, plug it back in, and wait two minutes for it to fully restart. Then run the speed test again on the wired device.
If the speed is still low after a restart, the problem is either your line itself or your modem hardware. Call your ISP and tell them your wired speed test is showing [the number]. They can see on their end whether the line is delivering the speed it should, and they can send a technician if it is not. Do not tell them your WiFi is slow — that wastes time because they will assume it is your router.
WiFi signal strength and distance are the most common causes of slow speed
If your wired speed is good but your WiFi speed is slow, the problem is your WiFi signal. WiFi travels through air and through walls, and the farther you are from the router, the weaker the signal gets. A device in the next room might see 80 megabits, and a device in the bedroom two rooms away might see 20.
Move closer to the router and run a speed test again. If the speed jumps up, distance is your problem. The fix is either to move the router to a more central location, to buy a second router or WiFi extender to cover the far end of your home, or to run ethernet cable to the rooms where you need speed.
Walls, especially walls with metal studs or pipes, block WiFi signal. A router in a basement or closet will have weak signal upstairs. A router in a metal cabinet will have weak signal everywhere. If you cannot move the router, moving it out of a cabinet or off the floor usually helps.
Other WiFi networks on the same channel are interfering with yours
WiFi routers broadcast on channels, and if your router and your neighbor's router are both using the same channel, they interfere with each other. This is especially common in apartments. You cannot control your neighbor's router, but you can change yours.
On a 2.4 gigahertz network (the older, longer-range band), use channel 1, 6, or 11 — these do not overlap with each other. On a 5 gigahertz network (the newer, faster band), there are many more channels and overlap is less common, but it still happens. Log into your router's settings — usually by typing 192.168.1.1 into a web browser — and look for the WiFi channel setting. Try a different channel and run a speed test. If it is faster, you found the problem.
Many modern routers have an auto channel setting that picks the least crowded channel automatically. Turning that on is simpler than manually testing channels.
Too many devices using the connection at once will slow everything down
Your internet line has a total capacity. If ten devices are streaming video, downloading files, or running updates at the same time, they are all sharing that capacity and each one gets slower. This is not a malfunction — it is how networks work.
Check what is connected to your WiFi. On most routers, you can see this in the settings page. Look for devices you do not recognize or devices that should not be using the network. A smart TV, a security camera, or a phone doing a background update can use significant bandwidth without you noticing.
If you have a lot of devices, the simplest fix is to disconnect the ones you are not using right now. If you need them all connected, you may need a faster internet plan or a second router to split the load.
Background apps and malware on your device slow it down
A slow speed test on one device while other devices are fast means the problem is that specific device, not your network. Background apps, browser extensions, and malware can all consume bandwidth or processing power without you seeing them.
On Windows, open Task Manager (press Ctrl+Shift+Esc), click the Network column to sort by network use, and look for apps using significant bandwidth. On Mac, open Activity Monitor, click the Network tab, and sort by Sent Bytes. Close any apps you do not recognize or do not need right now.
If you see an app using bandwidth that should not be, it may be malware. Run a malware scan with Windows Defender (built into Windows) or Malwarebytes. If you see a browser extension you do not remember installing, remove it. Browser extensions can inject ads, track your activity, or hijack your connection.
Frequently Asked Questions
Why is my speed test fast but websites still load slowly?
Speed tests measure raw bandwidth, but website loading depends on latency (how long it takes data to travel) and server response time too. A fast speed test with slow websites usually means the website's server is slow or far away, not your connection. Try a different website to see if the problem is everywhere or just that site.
Does restarting my router actually do anything?
Yes, but only for the router, not the modem. Restarting the router clears its memory and reconnects all your devices, which can fix WiFi problems. Restarting the modem is what fixes line speed problems. If you have a combined modem-router unit, restarting it does both.
Why is my speed slower at night than during the day?
More people are using the internet at night, so your ISP's network is more congested. This is especially common in areas where many people share the same line. If speed is consistently slow at night, you may need a faster plan, or your current plan may be oversold in your area — call your ISP to ask.
Can my ISP see what websites I visit and slow down certain ones?
Yes, they can see which websites you visit, and some ISPs do slow down certain types of traffic like video streaming. This is called throttling. If you suspect this is happening, run a speed test, then try streaming video and run another test. If video streaming is much slower than the test, contact your ISP to ask whether they throttle video.
What speed do I actually need for normal use?
For email and web browsing, 10 megabits is plenty. For video streaming, 25 megabits per device is safe. For online gaming, 5 to 10 megabits is enough, but low latency matters more than speed. If you have multiple people streaming at once, add 25 megabits for each person.