Whether you’re streaming on the bus or scrolling socials in the park, you’re using data. But how exactly does it work, and how can you keep an eye on it?

Mobile data is your connection to the internet when you aren’t on Wi-Fi. It allows you to browse the web, use apps, and stream music or video wherever you have a signal.

Data is measured in bytes. You'll usually see this written as:

• KB (Kilobytes)
• MB (Megabytes)
• GB (Gigabytes)

There are 1,024 KB in a MB, and 1,024 MB in a GB. Everything you do online sends (uploads) and receives (downloads) data, and both count towards your total usage.

We use a real-time system to track your data usage as it happens. Every time your phone connects to the internet, it asks our system for permission to start a "session."

Because your phone and our system might measure these sessions slightly differently (especially with background apps), the data usage shown in your phone's own settings might not exactly match your iD Mobile bill. Our system is the one we use to calculate your remaining allowance.

The quickest way to check how much data you have left is via the iD Mobile app or website. You can also call our automated service on 7777 from your iD Mobile SIM.

For a full guide on checking your allowance, read the article below:

Worried about running out of data or racking up a bill? Here are three easy ways to stay in control.

1. Enable ‘Low Data Mode’.

This setting stops apps from guzzling data in the background. Here’s how to switch it on:

I’m using an iPhone:

I’m using a Samsung Galaxy:

Most other Android phones:

2. Download before you go.

Apps like Netflix, Disney+, and Spotify let you download content while you're on Wi-Fi so you can watch or listen offline later. It saves a huge amount of data!

3. Set a Bill Cap.

This is the ultimate safety net. You can set a monthly spending limit (Bill Cap) in the iD Mobile app. Once you reach that limit, we’ll stop any chargeable usage so you can't overspend.

We believe help should always be free. That’s why you can access the following emergency, support, and charity websites without using a single byte of your data allowance (zero-rated):