Mobile data: how to tell what you use and what you need

You use your smartphone to browse the web, update your social media, count your steps, stream music and watch your favourite TV shows. But how much mobile data are you using and is your data allowance working for you?

Understanding your data usage is key to finding the right mobile phone deal...

Written by

Matthew Brewer

Broadband and mobile expert

Last Updated

12 APRIL 2022

7 min read

What is mobile data?

Mobile data is the information you send or receive when you use the internet on your phone outside of WiFi. Whenever you use your phone network to access the internet when you’re out and about – to browse web pages, send an email or stream video – you’re using your mobile data.

Whether you’re on a contract or a SIM-only deal, your phone tariff will include a certain amount of mobile data to use each month – your monthly data allowance. Go over that limit and you could be hit with extra charges, or go under and you’ll be paying for data you don’t need. So, it’s important to set yourself up with the right amount of data for your needs.

How is mobile data measured?

Data is measured in bytes. Different internet activities require different amounts of data, depending how complex they are. So, for example, streaming a movie will use a lot more bytes than sending an email.

Mobile data packages are usually sold in bundles of megabytes (MB) or gigabytes (GB). One MB is 1,000 kilobytes (KB) and 1GB is made up of 1,000 MB. How much you need depends on your usage.

Bear in mind that when it comes to data size, we’re talking bytes, not bits. Bits relate to the speed of your connection and how quickly that data is uploaded to or downloaded from your device. To tell them apart, bytes are uppercase (1 megabyte = 1MB) and bits are lowercase (1 megabit = 1mb).

How much data do different tasks use?

Whether you’re on Instagram, sending an email or downloading an app, it all uses data and counts towards your monthly data cap. But, by how much?

To give you an idea of how much everyday internet activities eat into your data allowance, here are some examples:

Online activity	Data used
Send an email with an attachment	300-500KB
One hour browsing the web	10-90MB
Download a song	4-5MB
Stream one hour of music on Spotify	70-150MB
Spend one hour on Facebook	20-150MB
Spend one hour on Instagram	100MB
Spend one hour on Twitter	360MB
Online gaming for an hour	40-80MB
Stream an hour of SD video	700MB
Stream an hour of TV on Netflix	1GB
Download a HD movie	4-5GB

Estimates on data usage vary because it’s not just about what you’re doing online, but how you’re doing it. Sending an email costs very little in terms of data, unless you’re sending photos or large documents as attachments. Browsing the web will use up more data if you’re visiting sites with lots of images and embedded videos. And your data usage on social media will vary considerably depending on whether you’re just browsing or if you’re posting regularly and uploading videos.

How much mobile data do I need?

Mobile data users tend to be classed in one of three groups, depending on how often they use the internet on their phone outside of WiFi.

Light users – don’t spend much time online. They may use mobile data to check their emails or scroll through social media during their commute or lunch hour, but no more than an hour a day. Light data users will usually need a data allowance of 1-5GB.
Medium users – will go online more often to browse the web or social media, and occasionally play games, stream music and watch videos. Medium data users will usually need a data allowance of around 6-10GB or more, depending on how much they use their phone for entertainment.
Heavy users – just can’t live without a million apps, and upload, download and stream TV, movies and songs constantly. Heavy data users might need a monthly limit of at least 20GB and in some cases, could be better off with an unlimited data allowance.

This is only a general guide. The most accurate way to find out how much data you need is to check your current data usage.

How can I check my data usage?

Most smartphones will show you how much data you’ve used so far in your billing cycle and how much you have left. You should also be able to see which apps have been eating up most of your data.

Check data usage on an iPhone

Go to phone settings and select ‘mobile data’. You’ll be able to see how much data you’ve used in the current period and which apps are using the most data. From here you can turn off permission for these apps to use mobile data.

Check data usage on an Android phone

Go to the settings and look for ‘data’ or ‘data usage’. It may be in a menu called WiFi & Network or Connections. You should be able to change the data usage period shown to match your billing cycle. Select mobile data usage to see which of your apps are using up your data. You can also turn on data saver to stop apps from using your data to run in the background.

How can I keep track of my data usage?

Some Android phones will let you set a data warning to notify you if you reach a certain limit. If that warning pops up, you can choose to turn off mobile data for the rest of the billing period and rely on WiFi or buy a bundle of extra data to get you through.

If your network provider has a customer account app, it’s worth downloading it (on WiFi, of course) so you can easily keep track of how much data, minutes and messages you have left for the month – to avoid any extra charges.

There are also third-party apps you can download that will monitor your data usage and show you how your data usage fluctuates day by day.

How can I reduce the amount of mobile data I use?

As well as getting the right data allowance for your phone, here’s some advice to avoid those nasty extra charges if you’re not on an unlimited package:

Be aware of file sizes when downloading and uploading. If you can, leave any hefty downloads and uploads for when you’re on WiFi.
If you’re streaming a TV show or movie using data, consider watching a lower-quality version to save data, for example, SD instead of HD.
Try to use WiFi whenever possible.
Stop your apps refreshing automatically.
Watch out for apps that are draining your data in the background. Turn off permission to use data for data-hungry apps you’re not using.
Download music, movies and TV shows on WiFi to watch on your commute.
Use apps like Pocket to download web pages on WiFi to browse when you’re out and about without using data
If you need directions when you’re out and about, download an offline map of the area on Google maps so you won’t need to use more data.
Be careful when going abroad, as you could face data roaming charges.

How can I find the best mobile data deal?

First, you’ll need to work out how much data you use. If you’re overpaying for your data or your allowance isn’t big enough, negotiate a more suitable tariff with your network provider.

If your data usage varies month by month, then a flexible contract might be best for you. Some network providers will allow you to turn features on and off on a monthly basis so you can increase your data allowance, for example, if you know you’re going to be away from WiFi a lot and relying more on your mobile data. Other networks offer data rollover plans that let you use up any leftover data in the next billing period.

Where can I compare data packages?

Compare mobile phone deals with us today and see if you can save.

Frequently asked questions

Can I increase my data allowance?

If you’re coming to the end of your monthly data allowance but you have more browsing to do, then you can normally add extra data on to your bill as a bolt-on. This should work out cheaper than simply allowing your data to go over and incurring charges.

If you find that you’re consistently going over your data allowance, you could consider upping the limit on your monthly contract or finding ways to cut back on your data use.

Am I paying for data I don’t need?

Many of us are so concerned about going over our data allowance and incurring hefty charges from our network providers that we err on the side of caution, opting for a bigger data limit than we need. But there’s no point paying for something you’re not using.

If you’re worried about the cost of your phone bill and you’ve noticed you’re consistently using less mobile data than you’re paying for, then you can renegotiate your tariff with your network provider or start looking for a better deal.

How much does it cost if I go over my monthly data allowance?

It depends on your network provider and the tariff you’re on. Some network providers will warn you when you’re getting close to your limit and offer you the chance to purchase a bundle of extra data. Other networks will charge you by the MB once you’ve reached your cap. Make sure to read the terms of your deal carefully as overuse charges can end up very expensive.

Do faster connection speeds mean more data?

Technically no, the speed of your connection – whether that’s 3G, 4G or 5G – makes no difference to the amount of data you need to perform different activities online. However, you may find that with pages loading faster and faster, you’ll end up browsing more and using up more data.