WiFi Channel Width – 20 Mhz vs 40 mhz vs 80 Mhz Explained.

Numbers! Bank balance, High score – the higher they are, the better! And what about WiFi channel width with internet speed?

What if I told you, you could double your WiFi speed by changing your channel width? After all, 40 MHz is a bigger number than 20 MHz. And by that logic, is improving WiFi speed without effecting ethernet as simple as that, or does it come at a cost?

It’s not uncommon — many people don’t understand why 20 MHz vs 40MHz and even 80 MHz is necessary. But it’s true: WiFi channel width plays an essential role in determining network quality and speed.

Wi-Fi Channel Width: What Exactly Is It?

First things first, you can definitely increase (if not double) your Wi-Fi speed by changing the channel width from 20 MHz to 40 MHz. But (there’s always a but), it can increase the odds of interference from other wireless devices. To understand this, you need to know how Wi-Fi channel width works.

How does Wi-Fi Channel Width work?

To draw a similar analogy, think of your Wi-Fi signal like water. If the wave is wider, it will transfer more energy to the surrounding area; at the same time, it won’t be able to go very far. For that, you would need a more concentrated wave contained in a narrower channel.

Similarly, a wider wave would catch more interfering objects on its sides. 

Now, translate that analogy to wireless networking. A wider channel width will result in a better bandwidth closer to the router. The further you go from the router, the more chances of interference and cluttery signals. A wider signal would have a harder time penetrating through the walls as well.

How Is WiFi Channel Width Different Than No. Of Channels In 2.4 & 5 GHz Frequency Bands?

The number of channels and the channel width is easily confusable. When someone refers to the number of channels, those are indeed the number of channels available for data transfer. For instance, in the 2.4 GHz frequency band, there are 11 channels available in the US or 13 in Europe.

However, when someone refers to the channel width, it is the amount of bandwidth allocated to a specific channel. The channel width is the data rate (typically known as WiFi speed) achievable in a channel.

The channel widths vary depending on the WiFi standard. For example, in the (wireless networking standards) 802.11n and 802.11ac, the standard channel widths are 20, 40, 80, and 160 MHz. 40 MHz can carry twice as much data as 20 MHz while being more susceptible to interference. 80 MHz can have twice as 40 MHz, and so on.

In short, the no. of channels refers to the number of data transfer channels available, while the channel width is related to the amount of bandwidth (bits per second) assigned for a specific channel.

Now you have come to know what is WiFi channel width. Next, I will break down each type of WiFi channel width to better understand which suits your needs.

How To Choose The Ideal Wi-Fi Channel Width For Any Situation?

When adjusting the settings on our Wi-Fi network, we want:

  • Maximum throughput (or the maximum internet speed)
  • Maximum range and
  • Minimum interference

To make sure you get the best of all worlds, you need to set the channel width correctly. Here’s how you can do that and choose the ideal channel width for any situation.

i. 20 MHz

When you are in a 2.4 GHz band, it is recommended to use a 20 MHz channel width. The reason is that there are several overlapping channels in this band, and only 3 out of 11 don’t overlap. Therefore, it is better to sometimes compromise high speeds and go with the minimum interference with better-supported bandwidth.

For example, the tiniest of stutters in video streaming can ruin the user experience. Most people prefer waiting a few minutes while the video buffers (which gives you prep time for snacks) rather than facing these stutters mid-stream.

20 MHz WiFi Channel Width is preferred in the following situations where:

  • The wireless environment is congested because a 20 MHz channel provides a smaller bandwidth than wider channels – meaning fewer chances of interference with other devices,
  • A large number of clients need to be supported.

A 20 MHz channel can serve more clients than a wider-width channel like 40 and 80 MHz.

ii. 40 MHz

40 MHz is the most balanced channel width because it offers more throughput than 20 MHz without facing too much interference, as is the case with 80 MHz.

40 MHz is also best utilized in a 5 GHz frequency band because of fewer overlapping channels – 24 out of 45 don’t overlap. Additionally, 5 GHz is a relatively new technology and is far less crowded than 2.4 GHz, meaning even lesser chances of interference.

You should use a 40 MHz WiFi channel width when:

  • The wireless environment is less congested (typically in a 5 GHz frequency band),
  • You need to support high-bandwidth applications such as large file transfers.

If you’re wondering why you shouldn’t use 40 MHz in the 2.4 GHz frequency band, answered in the FAQ section below.

iii. 80 MHz

80 MHz is only advised for usage if you live in a secluded area, and interference is not a problem. You can maximize speed quality in this channel, but there’s a high chance of interference with only four or five non-overlapping channels.

Besides, you need to be very close to the router (within 15 feet) to utilize 80 MHz at its full potential. If you need high-speed internet, and you’re going to be so close to the router anyways, you’d be better off with hardwiring it. Click here to learn more about hardwiring internet.

You should only use 80 MHz WiFi channel width when:

  • There are minimal chances of interference (like walls and solid objects), and the wireless environment is uncongested,
  • You need high-speed internet for high-bandwidth applications,
  • You have a network that supports 80 MHz channel width in the first place.

iv. Auto

Some Wi-Fi routers have built-in settings that enable automatic detection of channel size. The router will automatically select a channel width depending on the network condition.

There are typically two such settings, and you should enable them if you aren’t tech-savvy and aren’t looking to optimize every tiny detail. The router will do that for you efficiently in most cases.

a) 20/40 MHz (auto):

This mode is also known as Dynamic Channel Width and is particularly useful in environments where the number of network devices connected changes frequently.

This mode is recommended for use in public places such as coffee shops, airports, subway stations, hotels, etc.

The device will use a 20 MHz channel width when there’s a lot of congestion and automatically switch to a 40 MHz channel width when the wireless environment is less congested, providing the best possible performance for the clients.

The best part is you won’t have to manually change the channel width each time the wireless network environment changes.

b) 20/40/80 MHz (auto):

The 20/40/80 MHz (auto) mode is just an extension of the previous mode. This mode takes it one step further and selects 80 MHz mode when the wireless environment is relatively free and less congested.

You might have noticed this on your university campus and experienced faster internet speeds during holidays or even at night when most students have gone home.

However, one thing to note is that 80 MHz is not allowed in most regulatory domains in 2.4 GHz frequency bands. It is only available in the 5 GHz bands. You will have excellent speed if you’re using a 5 GHz Wi-Fi network.

20 MHz

40 MHz

80 MHz

20/40 (auto) MHz

20/40/80 (auto) MHz

Use when the wireless environment

Is congested

Is less congested

Is very less congested
You can be very close to the router (<15 ft)

Is changing frequently

Is changing frequently


Goes farther

Doesn’t go very far

Less than 15 feet



Chances Of Interference



A Lot



Number of channels that can be used simultaneously

3 channels for 2.4GHz and 19 channels for 5GHz

2 channels for 2.4GHz and 9 channels for 5GHz

4 channels for 5GHz




Which is the best channel width for 5 GHz?

The best channel width in the 5 GHz bands depends upon the number of active network devices. If there’s congestion, use a 20 MHz channel width; however, if there are lesser chances of interference, use 40 or 80 MHz, or even 160 MHz for faster speeds. Although, you might need to get closer to the router, and you might become more prone to interference.

Is 40 MHz good for 2.4 GHz?

The 2.4 GHz frequency band is already quite crowded, considering many devices such as cordless phones, microwave ovens, and even Bluetooth devices operate in that band. Now, when you add a 40 MHz channel width to this crowded band, you’re bound to face some interference. So, 40 MHz is not suitable for 2.4 GHz in most cases.

Which Wi-Fi channel width should I use when too many devices are connected to Wi-Fi?

If too many devices are connected to the Wi-Fi, use a narrower channel width, such as 20 MHz. This will decrease the chances of data collision and improve the overall throughput of the Wi-Fi. You can also use the 20/40 MHz (auto) setting to automatically switch to 40 MHz and have faster internet when there are fewer active devices.

Is 160 MHz Wi-Fi good?

160 MHz is suitable if the network environment isn’t congested but free. It can supply faster Wi-Fi speed than 80 MHz but is also very susceptible to interference. It doesn’t have a decent range, so you’ll have to be in the same room as your router.

Is there any downside to using a wider channel width?

Yes, there are a few downsides to wider channel widths like 80 MHz and 160 MHz. These are; interference with other network devices, lesser range, and compatibility issues – many devices don’t have the functionality to support wider channel widths. Additionally, wider channel width consumes more power as well.

Final Thoughts

Wider channel widths can give you faster WiFi speeds, but if you have a weak signal from router, you can get better rates with a narrow channel.

Speed and Interference of WiFi channel width between 20 Mhz vs 40 Mhz vs 80 Mhz

If the signal’s an issue, you can try improving the signal by installing more access points rather than settling for a lower MHz channel. Or, you can avoid all that and get maximum internet speeds by hardwiring your internet at home.

In conclusion, you’d want a WiFi channel width ideal for your environment. A narrow channel width such as 20 MHz penetrates further and has less interference. Wider channel widths have faster speeds but don’t go very far and can suffer from congestion issues.

Related: Do Routers Store Data?

I hope your tough time understanding the different WiFi channel Width of your WiFi connection is no more. If you liked the insights, you could support more people and us by sharing this post on social networks.

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