When your computer, tablet, phone or games console uses the internet to download and upload things, you are using data.
Downloading data includes retrieving information when you visit a web page, opening emails and attachments, streaming web radio, watching videos on YouTube and using Google Maps.
Uploading data is when you send an email, upload a photo or video, or have a video chat.
What is data?
Data is measured in kilobytes (KB), megabytes (MB) and gigabytes (GB). 1,024KB is equal to 1MB and 1,024 MB is equal to 1GB.
All BT Broadband plans now come with unlimited monthly data.
What uses up your data?
The amount of data you use depends on what you are doing. Video streaming or downloading a movie, for instance, uses more data than sending an email or uploading a photo.
Even then, the quality of the program can impact on data use, 4K/Ultra HD uses more data than high definition, which in turn uses more data than standard definition.
The number of devices using your connection also impacts on your monthly data use. If a family member is watching BBC iPlayer on their smartphone, another is playing Xbox Live and you are browsing the internet, you'll also use data.
What doesn't use data?
If you are a BT customer using BT Cloud over wi-fi it doesn't count towards your monthly broadband usage.
Watching the BT Sport online player or BT Sport app, doesn't count towards your monthly allowance over BT Broadband or a BT Wi-fi hotspot.
Watching BT TV channels or Video On Demand from BT Player doesn't count to your monthly allowance either.
How to check your broadband usage
If you are a BT customer, the My BT app makes it easy to check your broadband use, and you can check BT TV, landline and BT Mobile use.
Available to Android and iOS users, the award-winning app* allows you to check and pay your bill, download it as a PDF, check your service status and optimise your router, as long as you’ve got a mobile data (3G or 4G) connection or are connected to wi-fi.
Load the app and click 'Usage'
Download MyBT for Android.
Download MyBT for iOS.
Alternatively you can check your usage by logging in to: www.bt.com/mybt from a web browser using your BT ID. Go to My Bill – View your recent usage.