If you've found your Wi-Fi slowing to a crawl, there could be several causes. Ultimately, you want to get things running smoothly with as little as disruption as possible.

Fortunately, there are a few steps you can take to fix your Wi-Fi. So, let's take a look at what may be causing your slow Wi-Fi.

1. Router Positioning

The position of your router plays a critical role in your home Wi-Fi network. Even a slight shift in position could slow down your Wi-Fi. In fact, correct positioning is one of the many ways to improve the speed of your router.

High vs. Low

Like most people, you probably unpacked your new router, located a reasonable outlet, and left it on whatever was nearby: a shelf, a desk, or even the ground. As it turns out, router height does make a difference. Leaving your router on the ground or behind other objects usually results in noticeably worse performance.

Instead, put the router as high up as possible to extend the broadcasting range of the radio waves. This also helps clear the router of potential interference.

Concrete and Metals

Materials like concrete and metal are usually the biggest blockers of Wi-Fi signals. They are so effective at this that Faraday cages use the same materials to block all electromagnetic fields---they can even protect you from RFID hacks.

So, you may want to avoid placing your router in your basement, as a lot of concrete usually encloses this area. Other materials can impede your wireless network's performance, too. Make sure any other large objects don't block your router, either.

Distance to Router

The further away from your router you get, the weaker the Wi-Fi signal. Therefore, the best option is to place your router as close to your devices as possible. However, this is only practical if you have one main area where you tend to use your Wi-Fi-enabled devices.

Otherwise, you should place your router near the center of your home. After all, Wi-Fi broadcasts in 360 degrees, so it doesn't necessarily make sense to put it at one end of the house.

However, if your router's broadcast is noticeably weak or if your house is particularly large, then you may need to increase the range of those Wi-Fi waves. Wi-Fi extenders or repeaters are auxiliary devices that connect to the main router and repeat the signal to cover a greater area.

If you want to get scientific about your router placement, take a look at the Wi-Fi Strife project from London-based Software Engineer Jason Cole.

After moving into a new apartment, he mathematically modeled the property's Wi-Fi hotspots and coldspots. You can try this for yourself with the Wi-Fi Solver app, currently available for Android and Chrome OS.

Download: Wi-Fi Solver for Android | Chrome OS (Free)

2. Other Household Users

Hands resting on a laptop keyboard

Have you ever left a large download running on your PC? That may be the cause of your slow Wi-Fi. Downloading large files can take quite a toll on your Wi-Fi performance. Sometimes you can't avoid this---operating system updates can be massive, for example---but if you're running tasks that aren't urgent, try pausing them.

More likely, however, is that the people on your network---such as friends, roommates, or family members---are taking part in bandwidth-heavy activities like gaming and streaming Netflix. Fortunately, if this is the case, you can prioritize your network traffic by enabling Quality of Service in your router settings.

As humans are 60 percent water, and water can reduce the frequency of radio waves, people can also pose a connection problem. We're not suggesting that you remove all the people from your house, of course. But do make sure to keep your router out of the main areas where people congregate. The impact won't be monumental, but it may be noticeable.

3. Wireless Interference and Noise

You've probably never noticed, but there are wireless signals all around you wherever you go---and they're passing through you all the time. These signals come from our electronic devices, Wi-Fi routers, satellites, cell towers, and more.

Although Wi-Fi is usually on a different frequency than most of these devices, the amount of radio noise can still cause interference. However, you may be able to minimize some common causes of interference.

Microwaves

It turns out that microwave ovens can cause interference with your Wi-Fi network, an issue more common with older routers. This is because microwave ovens operate at a frequency of 2.45GHz, which is incredibly close to the 2.4GHz Wi-Fi band.

The 2.4GHz Wi-Fi band actually broadcasts between 2.412GHz and 2.472GHz, so there are times when the microwave frequency can overlap with the Wi-Fi frequency. When that happens, the data being transferred gets disrupted.

Most microwaves have the proper shielding, so no waves should be detected outside of the oven. But interference can occur with inadequate or poor shielding.

Bluetooth Devices

One of the other popular wireless connections, Bluetooth, also happens to operate at 2.4GHz. In theory, a properly designed device should be shielded in a way that prevents interference.

To avoid frequency clash, Bluetooth manufacturers use frequency hopping, where the signal randomly rotates between 70 different channels, changing up to 1,600 times per second. Newer Bluetooth devices can also have the ability to identify "bad" (currently in-use) channels and avoid those. But interference can still occur, so try moving the router away from Bluetooth devices.

Experiment by turning your Bluetooth devices off to see if this is the cause of your troubles, especially if they are older Bluetooth devices without channel management.

Christmas Lights

Strangely enough, Christmas lights (or fairy lights) can be a devious culprit in slowing down your Wi-Fi. The effect is caused by these lights emitting an electromagnetic field that interacts with your Wi-Fi band. Flashing lights are particularly problematic.

But you aren't even immune with modern LED lights. Some LED strings have flashing chips built into each lamp, and these create an interfering electromagnetic field.

In reality, all other kinds of electric lights can cause interference by emitting electromagnetic fields like this, but the effect is close to negligible in most cases. However, you should keep your router away from electric lights just in case.

Background Noise

Information designer Richard Vijgen created the mobile app Architecture of Radio. It uses public information on satellites and cell towers, along with Wi-Fi information and GPS location, to create a map of all the invisible signals around you. While the app isn't intended as a measurement tool, it helps to visualize the digital signals all around us.

Download: Architecture of Radio for Android | iOS ($3)

4. Your Neighbors

Laundry line connecting two apartments

Nearly every household has its own Wi-Fi network, which can create channel overlap. This can cause issues in a townhouse but is especially problematic in housing complexes and apartments with many routers nearby.

Channel overlap is mostly an issue for routers that can only broadcast at 2.4GHz, or if you have devices that can only receive a 2.4GHz wireless signal. This is because there are only 14 channels to transmit on. Two routers broadcasting on the same channel at the same frequency will interfere with each other.

That's why you must pick a proper channel in your router settings. Modern routers can choose channels for you automatically, but sometimes it's better to investigate and find the best Wi-Fi channel for your network. You should also keep your router up-to-date and regularly check for suspicious devices on your network.

5. Your Router

Illustration of a generic router

If you've tried all the above fixes and are still suffering from slow Wi-Fi speeds, you may need to consider more substantial action. Many of us use the router assigned by our ISP or otherwise use an older router. This could also be the cause of your lagging network. Older routers may not support bandwidth-preserving features, automatic channel switching, or Quality of Service.

Additionally, ISP routers are usually basic devices, intentionally lacking many of these features to lower the cost. If within your means, you could consider upgrading your router to speed up your Wi-Fi. Slow internet speed is only one of the reasons to replace your ISP's router, though.

When it comes to purchasing a new router, there's a lot of choices out there. Before making a decision, take a look at the best routers for long-range and reliability. If this isn't something you can invest in at the moment, you could check out how to boost your Wi-Fi signal, instead.

How to Fix Slow Wi-Fi Speed

Identifying the cause of your slow Wi-Fi can be a challenge. From router placement to the people in your home, there are many possibilities. If you've exhausted the physical explanations for your sluggish network, then it might be time to turn to the digital.

Take the opportunity to change your DNS settings to see if that helps. If the slowdown is isolated to your mobile devices, it's worth considering that there may be reasons your smartphone has slow internet speeds.