Why is my internet slow?

Why is my internet so slow?

Fact Checked Fact Checked

There are plenty of reasons why your internet is so slow. Canstar Blue’s telco experts have broken down 10 reasons why this may be the case and provided tips on how to fix your slow internet.

There could be high internet traffic in your area or through your provider, you could have devices on your local network soaking up your bandwidth, or you could simply have a slow plan. On top of this, your modem or router might be faulty or there could be problems with your internet provider in your area. Whatever the problem is, we’re here to help with some easy troubleshooting tips.

NBN plans you might be interested in

The following table shows a selection of sponsored unlimited data Standard Plus Evening Speed (NBN 50), and Premium Evening Speed (NBN 100) plans on Canstar Blue’s database with links to referral partners.

Unlimited Home Standard (NBN 50) Plans

The following table shows a selection of published unlimited NBN 50 plans on Canstar Blue’s database, listed in order of standard monthly cost (excluding discounts), from the lowest to highest, and then by alphabetical order of provider. Use our comparison tool above to see plans from a range of other providers. This is a selection of products with links to referral partners.

Unlimited Home Fast (NBN 100) Plans

The table below shows a selection of published unlimited NBN 100 plans on Canstar Blue’s database, listed in order of monthly cost, from the lowest to highest, and then by alphabetical order of provider. Use our comparison tool to see plans from a range of other providers. This is a selection of products with links to referral partners.

1. There is an internet outage

It seems obvious, but if there’s an internet outage your speed could be affected. If your slowed-down speeds are new and unexpected, your NBN provider could simply be performing maintenance, or the network could be experiencing issues.

Quick fix

It’s best to look these things up on your NBN provider’s website, just in case it’s an issue that’ll be solved soon. Most providers will offer status updates during network outages or scheduled downtime.

2. Your internet connection may not be as fast as advertised

It’s not uncommon for an internet connection to run more slowly than is advertised via the provider. Of course, most providers like to be optimistic about their speeds, which is why you might see the wording of ‘speeds up to’ on the plan’s advertising. Your slow internet may not be a connectivity issue, but instead is running at a speed considered regular for your NBN plan.

Quick fix

A speed test will confirm just how fast your internet connection is in megabits per second (Mbps). You can run a free test online using our speed test tool below or through a variety of speed testing websites (such as Ookla or Google Speedtest); this way you get an accurate read from multiple sources on how well your connection is performing.

It’s worthwhile comparing the results from your speed test against the maximum speed of your internet plan. If you’re on the NBN in Australia, this is easy to check as your NBN provider lists both the maximum speed available on your plan and the typical evening speed you can expect on its website.

For example, the maximum possible speed of Aussie Broadband’s NBN 50 plan is 50Mbps, and its typical evening speed is 50Mbps. If your speed test results are similar to the plan’s typical evening speed listed on your provider’s website (say, within a margin of error of about 5Mbps), then it would appear nothing is wrong – you might just need a faster NBN plan. If you’re now thinking about a faster NBN plan, find a plan with our internet comparison tool, or check out the table below. If your internet is still so slow, it’s time to investigate further.

Test your NBN speed

Want to see just how fast your internet is? Test your NBN Speed below!

Learn more about your internet speed results

3. You have a virus or malware

If your internet is running at different speeds on different devices, you could have an infected device. Viruses slow down your computer speed because they run in the background and use your computer’s resources to carry out their actions.

Quick fix

Perform a virus scan with your antivirus software. If no viruses are found, consider it an anomaly, re-do the speed test, and continue to troubleshoot.

4. The modem-router needs rebooting

A person disconnecting an ethernet cable from a modem

Computers tend to get a bit slow when they are left on for too long. Programs running in the background, hardware scans or start-up programs can build up over a long day of using your computer and slow it down.

Quick fix

‘Turning it off and on again’ can actually be a simple fix, especially on your modem-router. Click the power button on the back of the modem-router and wait a few moments, then turn it back on again. It’ll take a few minutes for your modem-router to boot back up, but once it’s back on and connected to the internet, run the speed test again and see if it improves. 

5. Multiple devices downloading at the same time

Sometimes slow internet can be caused by simultaneous downloads in your home, as the bandwidth is divided between multiple users or devices. For example, if you are downloading a video game and run a speed test, you might notice the speed test result is lower than it should be. This is because a large amount of bandwidth is being allocated to the video game download. The same can be true of background updates for phones, computers and consoles, along with streaming on services like Netflix and Stan.

Quick fix

The simple fix is to stop those downloads. If the problem is automatic updates, consider disabling those on your devices. Once you’ve stopped all the downloads that might be using up bandwidth, run another speed test. If your internet is as fast as it should be, the problem might be fixed. If not, there are more solutions to try.

6. Your WiFi signal isn’t optimised

Woman wondering why her internet is slow

If you’re noticing that your WiFi is particularly slow or unstable, it may be that your modem isn’t powerful enough to cover your entire home, isn’t placed in the best position in your home or it’s on a WiFi channel that is congested with other modem-routers in your home or building.  

Quick fix

Typically, your modem will be assigned to channel one, but you can try switching it to any available channel for better results. Again, finding the WiFi channel settings varies from modem to modem, and isn’t the same for every device, so look up a guide on your specific modem-router. Once you’ve done this, run another speed test, and see if it’s better than before.

If you can, try moving your modem-router to a more open space, so that it can cover more of the home within its WiFi range. While you’re doing this, try moving your modem-router around the home to find the best performing area. This isn’t a viable solution for wired internet types, but is fine for mobile broadband and home wireless broadband.

Try moving around any objects that could be causing the WiFi range to be limited. Once you’ve moved some furniture around, perform another speed test and see if things have improved. Needless to say, keep the modem-router away from objects that could cause interference, such as microwaves, cordless phones, baby monitors and devices that use Bluetooth.

If your internet is still slow, consider buying a new modem-router or, for bigger homes, a mesh WiFi system.

Read more: How to boost your WiFi Signal

7.  It’s a website issue

If you are having trouble accessing one particular website, but are able to visit other websites on the internet, the issue probably doesn’t lie with your connection. Instead, it is probably an issue with that specific website.

Quick fix

Luckily, there are websites (such as ‘Down for Everyone’) that can help you. Simply type in the URL or name of the website you are struggling with, and the page will let you know if it’s down for everyone, or just you. If it’s just you, it indicates a problem with your internet, while if it’s everyone, it’s a problem with the website and you’ll just have to wait it out.

8. Your DNS server isn’t getting the job done

A Domain Name Server (DNS) is a service provided by your Internet Service Provider (ISP) which allows you to use the internet. A DNS identifies and maps IP addresses, which are made up of numbers, and translates them into recognisable domain names, like canstarblue.com.au. If your DNS is affected by large amounts of traffic or the cache is corrupted, it won’t function properly and cause your internet to slow down.

Quick fix

Changing your DNS can definitely improve your speed. Typically, when you sign up for an NBN plan you’ll be assigned the DNS server of your ISP, but switching to alternative DNS servers can lead to a faster speed.

To change your DNS server on a Windows PC:

  • Step one: Search for ‘view network connections’ in your Finder search bar
  • Step two: Right click on your internet connection and select ‘Properties’
  • Step three: Select IPv4, then Use the Following DNS Server Addresses

From here you can enter the DNS server of your choice. It might be worth looking up a good DNS server, but here is a good one to start with – Google’s own public DNS server. Enter ‘’ in the primary section and ‘’ in the secondary section. After changing this over (applying the changes and making sure they save) run another speed test, and see if things improve.

To change your DNS server on a Mac:

  • Step one: Open ‘System Preferences’
  • Step two: Select Network > Advanced > DNS tab
  • Step three: Select the + sign located at the bottom left of the window, to add a new DNS server

From here you can enter the DNS server of your choice. A good one to start with is the Google Public DNS server, which is (with the secondary DNS being Then, click ‘OK’, followed by ‘Apply’, to save the changes. Run another speed test, and see if the problem is solved.

9. Your modem-router needs a firmware update

Keeping your modem’s firmware up to date is an easy way to avoid slow internet. Firmware is a type of software that allows the programs on your modem to run. Without updated firmware, modems will struggle to perform the tasks required for good internet speeds. Most modems today typically update firmware automatically, but some will still need you to approve updates in the backend.

Quick fix

Simply log on to your modem-router’s website and navigate to the updates section. This section varies from modem to modem, so it might be worth looking up a guide on your specific modem-router. Once this is done, run another speed test, and see if the problem is fixed.

10. Your Quality-of-Service feature is affecting your internet speed

Most routers offer a Quality of Service (QoS) feature which can help speed up your internet, in one or two places. A QoS throttles the bandwidth on some activities it deems less important and delivers the extra data to high priority internet activities. A QoS can be controlled remotely using optimisation features like traffic prioritisation, congestion control and bandwidth allocation. QoS is particularly useful in areas with high traffic. However, a QoS feature can also be a culprit for poor internet speeds. It can slow down upload speeds as well as general internet use.

Quick fix

If your QoS feature is not turned on, run an internet speed test before you turn it on and another one afterwards. If there is a difference between the results, the QoS is most likely slowing down your computer. You can switch the QoS off on your router.

If your QoS is already turned on, run an internet speed test before and after. If your computer runs slowly without the QoS, you may need to look elsewhere to find what is making your internet so slow.

Read more: Six ways to increase internet speeds 

Why is my new NBN connection slow?

If you’ve opted for an NBN connection, you’d expect it to work properly when you’re first connected. However, as with any internet connection, it’s not immune to issues, although you may be able to solve it on your own. Try these tips to potentially solve your slow NBN connection:

  • Restart the modem
  • Check how many devices are currently using your internet connection
  • Do a speed test
  • Try using it outside of heavy traffic periods

If your NBN connection is still slower than advertised, contact your provider to see if there’s an issue with the connection itself, as it may not have been installed properly. If the problem persists, contact your provider about a new plan, or opt for a new provider altogether.

Read more: How to test and benchmark your NBN speed.

Contact your NBN provider

If you have tried everything on this list but are still asking, ‘why is my internet so slow?’ it’s time to contact your NBN provider. The problem could very well be faulty hardware on the NBN provider’s part, such as wiring to the home or a problem with the local node. It could even be something within the home, such as a faulty modem-router or a dodgy ethernet cable. Needless to say, you shouldn’t put up with a service that isn’t working properly.

Your NBN provider will likely spend some time on the phone with you before sending a technician out to analyse the problem. When the technician is sent out, they will investigate the issue and will have a hands-on idea of what could be wrong with your internet speed.

Don’t try and contact NBN Co directly, as this isn’t how they handle faulty hardware matters. You’ll need to go through your NBN provider first.


Using a VPN may slow down your internet speed. Whilst using a VPN provides you with extra security, those extra layers can also be responsible for slowing down your internet as the extra travel required between the VPN and the encryption process can take time and cause your internet speed to lag.
High internet traffic volume can occur when living in a busy/crowded area, when too many people are on the WiFi at the same time, and is going to slow down your internet speeds. Typical evening speeds listed on internet plans account for higher traffic times, for example during the evening when more people are likely to be at home and online. 



Image: Carballo / Shutterstock

Emma Bradstock
Telco Specialist
Emma Bradstock has been an authority on consumer phone, internet, technology and streaming markets in Australia for over 5 years. She holds a Bachelor of Arts in Communications and Media from Macquarie University and has over a decade of professional writing experience in print and digital media.

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