What actually slows your internet down

Internet speed depends on three separate things, and fixing one won't help if the others are broken. Your connection speed is what your internet service provider sells you — usually measured in megabits per second (Mbps). Your device speed is how fast your computer or phone can use that connection. Your network speed is how fast data moves from your modem to your device, which depends on distance, walls, and interference.

Most people blame the ISP when the real problem is one of the other two. If your ISP promises 100 Mbps but you're getting 40 Mbps on a speed test, that's a real problem worth calling them about. If your ISP promises 100 Mbps and you're getting 95 Mbps but your video calls still lag, the problem is your device or your network, not your connection.

Key Takeaways

  • Run a speed test on your device while standing next to your router to find out whether your problem is the connection itself, your network, or your device.
  • Moving your router to a central, elevated location and away from microwaves and cordless phones can fix slow speeds without calling your ISP.
  • Restarting your modem and router clears temporary memory buildup and fixes many speed problems, but you have to wait 30 seconds between unplugging and plugging back in.
  • If speed tests show you're getting less than 90 percent of what you're paying for, contact your ISP with the test results and ask them to check your line.
  • Older routers (more than five years old) and devices with weak processors can't use fast connections even if your ISP is delivering the speed.

Test your speed before you do anything else

Visit speedtest.net or fast.com on the device that feels slow. Run the test twice: once while standing next to your router, and once from the room where you normally use the internet. Write down both numbers.

If the number next to your router is much higher than the number from your usual spot, your problem is network speed — your router isn't reaching far enough or something is blocking the signal. If both numbers are low and match what you're paying for, your ISP is delivering what they promised and something else is wrong. If both numbers are much lower than what you're paying for, your ISP connection itself is the problem.

Fix network speed by moving your router

Your router sends a radio signal, and walls, distance, and other devices interfere with it. Place your router in a central location in your home, elevated off the floor — on a shelf or mounted on a wall works better than on the ground. Keep it away from microwaves, cordless phones, baby monitors, and wireless speakers, which all broadcast on the same 2.4 GHz frequency that most routers use.

If your router is in a back bedroom and you use the internet in the front of the house, moving it to a hallway or living room will often double your speed without any other changes. Avoid putting it in a closet, cabinet, or corner — the signal needs room to spread.

Restart your modem and router the right way

Modems and routers store temporary data in memory, and that buildup can slow your connection over time. Unplugging them clears that memory. The catch is that you have to wait the full 30 seconds before plugging them back in — plugging them back in after 5 seconds doesn't work.

Unplug your modem first (the device that connects to your ISP's line), wait 30 seconds, and plug it back in. Wait for all the lights to stop blinking and stabilize — usually 2 to 3 minutes. Then unplug your router, wait 30 seconds, and plug it back in. Wait another 2 to 3 minutes. Run a speed test. Many speed problems disappear after this step alone.

Check what's using your bandwidth

Even if your connection is fast, it can feel slow if something is using all of it. 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 section — anything using more than a few Mbps is eating your bandwidth.

On Mac, open Activity Monitor (search for it in Spotlight), click the Network tab, and look at the Sent Bytes/sec and Recv Bytes/sec columns. Anything consistently above 1 MB/sec is using significant bandwidth. Common culprits are Windows Update, cloud backup services like OneDrive or Google Drive, and streaming apps running in the background. Close or pause the ones you're not actively using.

Update your router and check your device

Routers have firmware — software that runs on the device itself — and outdated firmware can slow your connection. Log into your router's settings (usually 192.168.1.1 or 192.168.0.1 in your browser address bar, or check the sticker on the back of the router). Look for a Firmware or System section and check for updates. If one is available, install it and let the router restart.

If your device is old, it might not be able to use a fast connection. Phones and computers from more than five years ago often have processors or network cards that max out at lower speeds. If your speed test next to the router shows your ISP is delivering the speed but your device feels slow, the device itself is the bottleneck. Upgrading to a newer device is the only real fix in that case.

Contact your ISP if the connection itself is slow

If your speed test next to the router shows you're getting less than 90 percent of the speed you're paying for, your ISP connection is the problem. Take a screenshot of your speed test result and contact your ISP's customer service. Tell them your speed test shows you're getting X Mbps but you're paying for Y Mbps, and ask them to check your line for problems.

ISPs can run diagnostics on their end to see if there's a problem with your line, your modem, or the equipment in your neighborhood. Sometimes the fix is as simple as them sending a technician to replace your modem. Sometimes it means they need to repair the line itself. Don't accept "that's normal" as an answer — if you're paying for a certain speed, you should get close to it.

Frequently Asked Questions

Why is my internet fast on one device but slow on another?

Your devices connect to your router separately, so one device's problem doesn't affect the others. Run a speed test on both devices in the same location. If one is much slower, that device has a problem — maybe its network card is failing, or it's running something in the background. If both are slow in the same spot, your router or network is the problem.

Does changing my WiFi password make it faster?

No, but changing your WiFi security from WEP or WPA to WPA2 or WPA3 can help. Older security standards are slower. If you're still using WEP (very unlikely on modern routers), upgrading to WPA2 will noticeably improve speed. Check your router settings under Security or Wireless to see what you're using.

Will a WiFi extender or mesh system fix my slow speeds?

A WiFi extender repeats your signal to reach farther, but it uses half your bandwidth to do it, so it's slower than the original signal. A mesh system (multiple connected routers) is better because the routers talk to each other on a separate channel. If your main problem is that the signal doesn't reach, mesh is worth considering. If your main problem is that your connection is slow everywhere, mesh won't help.

How often should I restart my modem and router?

Once a month is a reasonable schedule for most people. If you notice speed dropping over a few days, restart sooner. You don't need to restart every day — that's a sign something else is wrong and needs fixing instead.