What actually determines your internet speed

Your internet speed depends on three separate things: what your internet service provider (ISP) sells you, what your home network setup allows, and what your devices can handle. Most people think they need to pay for faster service when the real problem is somewhere else — and paying won't fix it.

Start by testing what speed you're actually getting right now. Go to speedtest.net or fast.com on a device connected by ethernet cable (not Wi-Fi) to your router. Run the test at different times of day. Write down the results. This number is what you're paying for, or close to it. If it matches your plan, your ISP is delivering. If it's much lower, something between the wall and your device is the problem.

The speed you pay for is measured in megabits per second (Mbps). A 100 Mbps plan means you should see around 100 Mbps on that test. A 500 Mbps plan should show around 500 Mbps. Small variations are normal — you might see 95 Mbps on a 100 Mbps plan and that's fine. Seeing 50 Mbps on a 100 Mbps plan is not.

Key Takeaways

  • Test your actual speed with an ethernet cable at speedtest.net to see what your ISP is actually delivering versus what you're paying for.
  • If your speed test is much lower than your plan, the problem is usually your Wi-Fi router, its placement, or interference — not your ISP.
  • Moving your router to a central, elevated location and away from microwaves and cordless phones can fix slow speeds without paying more.
  • Older routers (more than five years old) often can't deliver the speeds your ISP provides, even if everything else is working.
  • If your ethernet speed test is low, contact your ISP — the problem is on their side and they should fix it at no cost.

Check whether your router is the bottleneck

Most slow internet complaints are actually slow Wi-Fi complaints. Your ISP might be sending 200 Mbps to your house, but your router might only be able to broadcast 50 Mbps wirelessly. The fix is not a faster plan — it's a better router.

Run that speed test again, but this time on Wi-Fi instead of ethernet. If the Wi-Fi number is much lower than the ethernet number, your router is the problem. If they're similar, your router is fine and something else is slowing you down.

Check how old your router is. If it's more than five years old, it probably can't handle modern speeds. Routers from 2019 or earlier often max out at 100 to 150 Mbps even when your ISP is sending much more. A newer router (2022 or later) with Wi-Fi 6 can handle gigabit speeds. You don't need the most expensive one — a mid-range Wi-Fi 6 router from a brand like TP-Link, ASUS, or Netgear costs $60 to $150 and will work fine for most homes.

Fix your router placement and interference

Where your router sits matters more than most people think. A router in a closet, behind a TV, or in the corner of your house will broadcast a weak signal. A router in a central location, elevated (on a shelf or wall mount, not on the floor), and away from obstacles will reach much farther and faster.

Keep your router away from microwaves, cordless phones, baby monitors, and wireless speakers. These devices use the same 2.4 GHz frequency that Wi-Fi uses and create interference. If your router has two bands (2.4 GHz and 5 GHz), connect devices that need speed to the 5 GHz band — it's faster but doesn't reach as far. Use 2.4 GHz for devices farther away or in other rooms.

If you have a large house and Wi-Fi is slow in distant rooms, a single router might not be enough. A mesh Wi-Fi system (like Eero, Netgear Orbi, or TP-Link Deco) uses multiple units to cover your whole house. These cost $100 to $300 depending on the size of your home, but they're much more effective than a single router in a corner.

Restart your modem and router properly

A restart actually fixes things about half the time, but most people do it wrong. Unplugging for five seconds doesn't work. You need to unplug both your modem and router, wait 30 seconds, plug the modem back in first, wait for all its lights to stabilize (usually two to three minutes), then plug the router back in.

The modem is the device that connects to the cable or fiber line coming into your house. The router is the separate device that broadcasts Wi-Fi. If you have a combo unit that does both, unplug that one device and wait the full time.

If restarting doesn't help and your ethernet speed test is still low, the problem is on your ISP's side. Contact them and tell them your speed test result. They can run diagnostics on their end and fix it. This is their responsibility — you shouldn't pay extra for something they're not delivering.

Upgrade your plan only if ethernet speed is low

Before you pay for a faster plan, make absolutely sure your current plan is the problem. Run that ethernet speed test one more time. If you're getting close to what you're paying for, a faster plan will help. If you're getting much less, upgrading won't help — something is broken and needs fixing first.

When you do upgrade, know what speeds are actually available at your address. Different ISPs serve different areas, and availability varies wildly. Some neighborhoods have gigabit fiber (1000 Mbps), others have cable (up to 500 Mbps), and some have only DSL (up to 100 Mbps). You can't get what isn't available, no matter how much you pay.

Check what your ISP offers by entering your address on their website. If only one ISP serves your area, you have no choice. If multiple ISPs serve you, compare their speeds and prices. Fiber is faster and more reliable than cable, which is faster and more reliable than DSL. If fiber is available, it's usually worth the cost.

Reduce the number of devices using your network

Every device on your Wi-Fi uses a piece of your bandwidth. If you have ten devices streaming video at once, each one gets a smaller slice. This is especially true on older routers or if devices are far from the router.

Check what's connected to your Wi-Fi. Go into your router's settings (usually by typing 192.168.1.1 into a browser, though this varies by router — check your router's manual). Look for a list of connected devices. If you see devices you don't recognize, they might be neighbors' devices connecting to your network by mistake, or they might be old devices you forgot about. Remove them.

If you're streaming video, downloading large files, or video calling while other people are using the network, speed will be slow for everyone. This isn't a problem with your internet — it's just how bandwidth works. If this happens often, a faster plan makes sense. If it's rare, it doesn't.

Check for malware or background programs

Malware and unwanted programs can use your bandwidth in the background without you knowing. Run a malware scan on your computer using Windows Defender (built into Windows) or Malwarebytes (free version available). On a Mac, run a scan with Malwarebytes as well.

Also check what programs are running. On Windows, open Task Manager (Ctrl+Shift+Esc), click the Performance tab, and look at Network usage. If something is using a lot of bandwidth and you don't recognize it, search the program name online to see what it does. On a Mac, open Activity Monitor, click the Network tab, and look for high bandwidth use.

Updates can also slow things down temporarily. If Windows or macOS is updating in the background, your internet will be slower until the update finishes. This usually takes an hour or two. Restart your computer to speed things up.

Frequently Asked Questions

Why is my speed test fast but everything still feels slow?

Speed tests measure raw bandwidth, not responsiveness. A website might load slowly because of server issues, not your internet. Try speed tests at different times of day. If they're consistently fast but websites feel slow, the problem is usually the website or your device, not your ISP.

Should I pay for a faster plan if I only use the internet for email and browsing?

No. Email and web browsing need only 10 to 25 Mbps. Video streaming needs 5 to 25 Mbps depending on quality. Video calls need 2.5 to 4 Mbps. If your speed test shows you're getting what you pay for and it's above 25 Mbps, a faster plan won't change how these things feel.

Can I get faster internet by changing my DNS?

Changing DNS (to something like 8.8.8.8) might help if your ISP's DNS is slow, but it won't increase your actual speed. It might make websites load slightly faster. It's worth trying, but it's not a major fix. Your router's settings let you change DNS, or you can change it on individual devices.

What's the difference between download speed and upload speed?

Download speed is what you use for browsing, streaming, and downloading files. Upload speed is what you use for video calls, uploading photos, and sending large emails. Most plans have much faster download than upload. If you do a lot of video calls or upload large files for work, check your upload speed too — it might be the real bottleneck.

Is satellite internet as fast as cable or fiber?

Satellite internet (Starlink, Viasat) has improved, but it still has higher latency (delay) than cable or fiber, which matters for video calls and online games. Download speeds can be decent (50 to 150 Mbps), but the delay makes things feel slower. Use satellite only if cable or fiber isn't available in your area.