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Broadband download speed calculator: find out your broadband download time

Want to find out how long a download might take? Considering a broadband upgrade and want to see how much faster your internet speed could be?

In this guide, you can use our download time calculator to get an instant estimate of how long a transfer will take and learn more about downloading and uploading and improving your download speed.

Broadband download time and speed calculator

Use the calculator widget below to find out how long a download will take.

Enter the size of the download in bytes (kilobytes, megabytes, gigabytes, etc.) and the speed of your broadband connection in bits (most likely megabits). Click the drop-down menus to switch between kilo/mega/giga and seconds/minutes/hours.

Download Time Calculator


Use our free speed test to find out your broadband speed.

You can also enter a time and file size to estimate the speed of a broadband connection or a time and speed to get file size.

How is download time calculated?

The equation for calculating download time is:

  • File Size in bytes / (Download Speed in bits / 8) = Time

For example:

  • 50MB / (10Mb/8) = 40 seconds

Of course, it’s much simpler to use the calculator above, especially when you get into the hundreds or thousands of megabytes.

What is the difference between bits and bytes?

Bits and bytes are both units of data, but they’re used in different ways for broadband.

Data transfer speed is measured in bps — bits per second. Most broadband speeds will be shown as megabits per second (Mbps, Mb/s, or Mb) though kilobits (Kbps, Kb/s, or Kb) and gigabits (Gbps, Gb/s, Gb) are also common.

Bytes are used to indicate data size or capacity, like the size of a file or a hard drive's storage space.

There are 8 bits to every byte. So at a speed of 1 megabit, a connection can transfer 1 megabyte every 8 seconds.

Upper and lower case is used to differentiate between them. Small b for bits (Kb, Mb, Gb), big B for bytes (KB, MB, GB).

What broadband download speed do I need?

Your broadband speed requirements will depend on what you plan to do with the broadband and how many people share the connection.

Frequent large file downloads or uploads are much easier with fast internet; the table below shows how long files of various sizes can take to download, and illustrates how much of a difference fibre broadband makes.

File size Broadband speed
  10Mb 35Mb 50Mb 65Mb 100Mb 500Mb
1GB 13.3 mins 3.8 mins 2.6 mins 2.1 mins 1.3 mins 16 secs
10GB 2.2 hours 38.1 mins 26.6 mins 20.5 mins 13.3 mins 2.6 mins
50GB 11.1 hours 3.2 hours 2.2 hours 1.7 hours 1.1 hours 13.3 mins
100GB 22.2 hours 6.4 hours 4.4 hours 3.4 hours 2.2 hours 26.6 mins

As you can see, even a cheap entry-level fibre optic deal with an average speed of 35Mb will significantly reduce download times compared to a 10Mb ADSL service.

Video streaming also benefits from faster broadband speeds as it will let you stream in high-quality HD and ultra HD. Without it, you may find viewing is often interrupted by buffering.

The other factor to consider is how many people will be sharing the connection because every person (or device) you add will reduce the available bandwidth.

ADSL broadband (which has an average speed of just 10Mb) can struggle to cope even with fairly light usage if more than one person is online at the same time.

Fibre optic internet is essential for shared or family homes. As a rough guide, allow a speed of 10Mb per person, plus another 10Mb for every person who is likely to be using it for things like file downloads and video streaming.

However, we recommend a minimum of 35Mb fibre optic broadband for everyone, even if you’re the only person using the internet. With this speed, you can easily stream HD video and download files in a reasonable time. And there are plenty of cheap fibre optic deals available, so it’s not much more expensive than ADSL.

How can I calculate upload time speed?

Calculating the time of an upload (where files are sent from your device to the internet) is exactly the same as working out a download time, except you’ll most likely have to change the speed when working it out.

Most broadband services have a slower upload speed in favour of quicker downloads (this is known as asymmetrical broadband). Some broadband is symmetrical, which means it has the same download and upload speed, but this is rare.

Use our broadband speed test to find out your current upload speed.

Why are my downloads and uploads taking longer than calculated?

The calculator shows the time it will take to transfer files at any given speed, but your connection will not continuously move data at the same rate. Speeds can fluctuate even during a transfer, and the performance of your broadband will change throughout the day depending on network traffic.

The speed can also be restricted by the connection of the server that is sending or receiving data. If a server is very busy, you will find that speeds are reduced as a result, even if your broadband connection appears to be working normally.

How to get faster download speeds

If your downloads are slower than expected, here are a few things you can do to improve the speed.

Switch off other devices and software on your Wi-Fi
Other devices sharing your broadband may be impacting the speed by reducing the available bandwidth. Switch off anything you don’t need to free up more bandwidth for your download.

Download from a different server
Sometimes a slow download is caused by the server sending you the file, rather than your broadband connection, so try getting the file from another site. If possible, choose a server close to your location.

Save big downloads for off-peak hours
Broadband networks can slow down during peak hours (typically 8am to midnight). Wait until late at night or early in the morning, and you might find the transfer is completed much sooner.

Use a wired network connection
Wired networks can be faster and more reliable than Wi-Fi so, when possible, connect your devices directly to the broadband router with a network cable.

Boost your Wi-Fi signal
If a network cable isn’t an option, there are ways you can improve Wi-Fi signal strength to get better speeds. Wi-Fi extenders are a cheap way to boost the signal in areas of your home where the network is weak. You should also ensure that the Wi-Fi router is in a central location in your home and is not close to any walls or appliances which may block the signal, especially fridges, microwaves, and cordless phones.

Reboot the Wi-Fi router
If your broadband is unusually slow and you’ve eliminated other causes, try switching it off and on. Often, power cycling your router to reconnect it to the network will improve broadband performance. This will disconnect every device on your Wi-Fi network while it reboots, so check with everyone in your home first.

Upgrade your broadband
If there's no way to improve your current broadband service, it may be time to consider upgrading to a faster package.

Here are some of the top deals currently available:

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But these are just a few of the offers available; enter a postcode into the Broadband Genie checker tool, or the box below, to see what else you could get in your area:

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