Data Calculator

GB is short for Gigabyte - and is equivalent to 1024 megabytes (MB) or 1,048,576 kilobytes (KB).

As a rough guide, 1GB of data would let you do one of the following:

• Watch one hour and 20 minutes of video at Standard Definition

• Stream roughly eight hours of high quality music (320kbps)

• Send or receive about 1000 emails

• Send over 1.5 million WhatsApp messages (without pictures or video)

The amount of data used to stream a movie will depend on the length of the film and how high you want the picture quality to be. Netflix say that viewing in High Definition (HD) uses 3GB per hour, while Standard Definition (SD) uses 0.7GB per hour.

With some modern films (such as Star Wars: The Last Jedi) lasting as long as two and a half hours that means, even at SD, it would take over 2GB of data to watch the whole movie.

Don't forget though, if you're using Netflix or iTunes, you can always download a movie or an episode on Wi-Fi to watch later - this won't count towards your monthly mobile data usage.

Streaming music uses surprisingly little data - but it does add up. On Spotify or TIDAL, 'High Quality' is set to 320kbps. That's just over 115MB per hour, which works out at about 1GB over eight hours.

On some music streaming apps (including Spotify and TIDAL) you have the option to listen offline. Simply download the albums or playlists you most listen to when you're connected to Wi-Fi and you can enjoy your favourite sounds without using up your monthly mobile data allowance.

Online gaming data usage can vary greatly. Using some online multiplayer games in real-time can use up to 100MB in a day and others much less. If you want to ensure gaming is included in your calculation, add the hours spent online gaming to the slider for socialising on our Data Calculator.

'Tethering' is using your mobile phone as a Wi-Fi hotspot to provide an internet signal for another device (such as a tablet or laptop.) The amount of data you use will depend on what you're using the tablet or laptop for. For example, streaming a movie on your tablet while tethered to your phone will use the same amount of mobile data as streaming the movie direct to your phone.

If you can't find what you're looking for in our Data Calculator, it's probably because it doesn't use a significant amount of data.

Using Siri, or Google assistant, for example uses very little data. Using Google maps or Maps uses very little too. This is because once you've input the journey, your phone downloads the map you need and 'caches' the information.

So if you can't see it on the list - you probably don't need to worry about it.

Please note: As apps become more sophisticated and cameras create higher resolution images and video, it is likely that your data consumption will increase. Don't forget to factor that in when you are choosing your plan.