Your Wi-Fi is slowing down, but why? With so many wireless devices in our homes now, even little flaws can take a toll on performance. In this guide, we'll take a look at common issues, why your Wi-Fi might be slow, and how to solve them.

1. Too Many Devices (Internet of Things)

smart iot hubs on shelf next to router

IP cameras, smart voice assistants, remote control lightbulbs, smart plugs, even your robot vacuum cleaner — our homes are increasingly filled with Internet of Things devices, each of which sits on the Wi-Fi network with its own IP address.

While your average lightbulb isn't going to send or receive a large amount of data, most home routers simply weren't designed to handle so many registered Wi-Fi devices at once. Past a certain point—usually about 30—you'll start experiencing dropouts.

Solution: Consider how old your router is and if you can afford to, upgrade to a newer model. I recommend Ubiquiti UniFi as the best for a high capacity scalable Wi-Fi, though it is expensive. You'll get better coverage, too, by adding access points wherever needed. For smaller homes, Ubiquiti AmpliFi is a more budget-friendly option.

diagram of network layout with multiple access points

If you're planning on blanketing your home with smart sensors, use Z-Wave where possible. It operates at a different frequency to Wi-Fi, so it won't cause interference. Note that Zigbee devices (such as Philips Hue bulbs) use the same 2.4Ghz frequency as Wi-Fi, so will cause interference.

2. Wireless Network Range and Signal Penetration

Where you place your Wi-Fi router is the single most important factor affecting the speed of your home Wi-Fi.

Wi-Fi routers transmit both a 2.4Ghz signal (often referred to as b/g/n) and 5Ghz (ac). The 5GHz network is faster—so why wouldn't you just disable the 2.4GHz network? Because the 2.4GHz signal has better penetration: it can go through walls and other solid objects more easily and travels further. A thick concrete floor or wall will stop the 5Ghz network entirely.

There's no need to worry about the exact technical differences, but you should understand that wireless speeds are impacted by solid objects, so the more things between your device and your router, the worse your network will perform.

Solution: Read our guide to getting the best Wi-Fi coverage and reposition the router as best you can.

Sometimes, it isn't possible to move the router due to the location of an incoming fiber optic or phone line connection. In that case, consider running an Ethernet cable to elsewhere in the house, then use an additional router just for Wi-Fi.

3. Too Many Users

Your internet connection is only so fast, and that speed is shared with every other user in the house and all of their devices. So as well as the obvious things like computers, phones, and tablets, you'll also find Smart TVs, game consoles, media streaming sticks, smart home hubs–all of which may be sending or receiving information at a particular point in time.

You may be surfing the web on your tablet while your Xbox is grabbing the latest DLC content, Windows is updating itself, and the set-top box is streaming an on-demand movie.

device list of home network clients

All these activities consume a little of your total available bandwidth. And it's not just when you're actively using them: automatic updates often occur without your knowledge. Some devices can even wake themselves up in order to update. Does Alexa slow down Wi-Fi? Probably not, but other Amazon devices can: in a 24 hour period, our Amazon Fire TV ate through nearly 10GB of video data.

Solution: First, check your router admin page to see if it lists the bandwidth devices are currently using, and see if you can identify a single culprit. If there's a particular application or type of activity you want to ensure is always performing its best, look into enabling Quality of Service. This setting "ropes off" a certain amount of throughput for either a particular device or a specific activity. Learn more about Quality of Service settings.

4. Old Network Cables

If your computer is plugged directly into your router, or if you're lucky enough to have Ethernet cabling throughout the house, it's worth checking the type of cabling.

While electrical cabling might last for 50 years or more, network cabling has undergone several important upgrades that affect the speed it can carry data.

selection of network cables-1

The easiest way to check is to look at the cable. You should see a Cat number specification somewhere:

  • Cat-5 is the oldest and slowest network cable still in use. Performance is limited to 100 Mbps.
  • Cat-5e is the most commonly used network cable today; it supports Gigabit Ethernet (1,000 Mbps).
  • Cat-6/6a is the fastest network cabling in common usage and supports up to 10 Gigabit (10,000 Mbs).

If you use Cat-5 cable for your computers or the backbone of your network, your Ethernet cable may be slowing down the Wi-Fi. Network cables can also be quite delicate. Use a cable tester to ensure each of the eight wires inside the cable is still connected to the other end.

Solution: Replace any Cat-5 rated or broken cabling you find with Cat-5e or Cat-6 rated cables. There is no need to upgrade to Cat-7 or Cat-8 cables; none of your devices (now or in the next decade) will see any speed benefit.

5. You're Using Powerline or Wi-Fi Extenders

Many people think that an easy solution to Wi-Fi woes is to buy an extender: a little box that plugs into your power socket and repeats the Wi-Fi signal to another part of the house. Some even use "Powerline" adapters that allow you to send network signals through your home electrical cables.

But in my experience, these devices fail to tackle the root of the problem and often just make things worse by adding interference.

Solution: If you have a large home and your Wi-Fi can't reach everywhere, consider a mesh Wi-Fi system or a UniFi system that allows you to add access points as needed.

6. Your Wi-Fi Channel Is Heavily Congested

One of the benefits of living in the middle of nowhere is that there are usually no other networks around me. In this case, I've used an Android app called Wifi Analyzer, which shows me that a device I'm reviewing is actually broadcasting its own hidden Wi-Fi signal, and my printer, both of which are interfering with my home network.

wifi analyzer screenshot

Download: Wifi Analyzer (Android)

For those in urban areas, particularly apartment blocks, you may be surrounded by hundreds of Wi-Fi networks. Unfortunately, they all take a little of the available frequency bandwidth.

Solution: You could try changing the channel number that you broadcast, but modern routers are smart enough to pick the best channel anyway. Therefore, your only option is to reduce the number of devices using Wi-Fi to enable better use of what little bandwidth you do have. If a device can be plugged in via Ethernet, it should be. Leave Wi-Fi for devices like smartphones and tablets that you don't have the option for.

7. Your ISP's DNS Server Is Slow

Not all DNS servers are made equal, yet these are fundamental to your internet connection. DNS is used every time you type a web address into your browser: it's like a phonebook that translates between the human-readable web domain, and the physical IP of the server it's located on. By default, you're using the DNS server provided by your ISP, but it's often slow and unreliable. If you find it takes a long time between typing in a web address, and seeing the first elements of the page load, it could be a slow or faulty DNS server.

Solution: You can change your DNS server to something a lot faster, and it's better for your privacy too. This can give you a small but easy speed boost to all your web browsing activities.

8. Your ISP May Be Throttling You

It's unlikely unless you're a heavy user, but many ISPs will deliberately slow down your internet if it detects usage of filesharing applications or once you reach a certain threshold. This is more common on mobile data connections than home broadband connections but does still happen.

screenshot of internet speed checker on router

You should have a good idea of what your typical internet speed is and check it regularly. If you find it's significantly reduced and no faults are being reported by your ISP, you may be being throttled or subject to "bandwidth shaping." Check your terms and conditions or for the existence of a "fair usage policy."

Solution: If this is happening to you, sadly, your options are limited. Either curtail your download activity or see if there's another provider that doesn't have the same draconian limits. If you're being throttled because your ISP has automatically detected the use of filesharing apps, use a VPN to hide your internet activity.

9. You're Using a Buggy USB 3.0 Port

The USB 3.0 standard brought incredible speeds, but the first version was buggy. It was later discovered that when certain USB cables or devices were plugged into an older USB 3.0 port, it would generate interference on the 2.4Ghz spectrum. That's the same frequency used by many wireless peripherals and Wi-Fi.

Solution: Unplug USB 3.0 devices and cables (the ports are usually blue) to check if they're generating interference. Many low-bandwidth devices such as wireless mice or keyboards can operate fine in an older USB 2.0 port (the black ones).

Related: How to Test Your Home Network Speed (And Decipher the Results)

Make Sure Your Network Keeps Up With Your Devices

While it's advisable to plan your network, you never really know what devices you'll add in the future. At first, just using the wireless router provided by your ISP is enough for a few devices to access the web. But you should continue to think about your needs as you add more and different devices, and learn the basics of home networking.

Image Credit: ginasanders/Depositphotos