Mobile broadband usage guide: what can you get for your gigabyte?

When it comes to mobile broadband there are a large variety of deals out there. To differentiate themselves from their competitors the mobile providers try to undercut their rivals in terms of price, extras, laptop deals and so on, with one of the key areas being usage allowance.

The most generous deal from Three currently offers up to 15GB while the more frugal amongst you can take deals as low as 500MB per month, or opt for a pay as you go (PAYG) deal where you pay either per day, or per GB. 

But what can you actually get for your gigabyte?

Firstly, it's important to remember that 1GB is equal to 1024MB, although for ease of calculation it is easy to just round that to 1000. Most forms of data that you will use are still measured in MB, with some smaller files measures in KB (1024KB = 1MB) or even B (1024B = 1KB).

Secondly, note the below info is only approximate – files are not created equal! Use this information as a guideline to how large files might be, but be careful and keep a close watch on your usage. Don't rely on any usage calculator that might be downloaded as part of your dongle software – these don't tend to be accurate, and claiming you used one will be no good as a defence to your mobile broadband service provider if you go over your limit and incur a penalty!

In addition, third party data calculators are also unreliable, no matter what they might claim – the only way to be sure how much allowance you have left is to check your account online with your mobile broadband service provider. Basically, if you're using a data counter for mobile broadband, don't rely on it.

So how much usage do I need?

This will completely depend on how you intend to use mobile broadband. For many mobile broadband users the service is a back-up for their fixed-line or business connection: they use a dongle with a laptop to browse the web and download emails when out of the office or on holiday, and not for data intensive tasks. These users are unlikely to get too close to a 3GB limit, let alone a 15GB one, unless they decide to watch a lot of streamed content (see below) or download massive work files.

However, if you're looking to use mobile broadband as a replacement for fixed-line broadband (where usage limits are far more generous and penalties less severe) you need to be careful. 

Work out what you're going to be downloading from our table below and also make sure to check out the excessive usages you may be saddled with, just in case. In truth, even as your main source of broadband a 15GB limit per month will normally be plenty – just take note of the really data-intensive uses below and if you're concerned keep close tabs on your account. 

Fair usage and excessive usage policies: charges

The cost of going over your usage limit can vary dramatically between providers on monthly contracts. We're not going to list all of the provider charges here as it's akin to painting the Forth Bridge; no soon as we've updated them, then one of the providers decides to change them again.

Suffice it to say, whoever you choose you're going to have to pay more than your usual 'per GB' rate for any excess data you use. On the plus side, of course, mobile broadband providers will always be happy to put you onto a more expensive tariff to give you a larger allowance; they're generous like that...

Mobile broadband usage calculator

As already noted above these are rough estimates based on information gathered from a variety of sources including mobile broadband providers and data published by companies such as Skype. Please read the notes below the table for more detailed descriptions that will help explain the variations in estimates.

1 hour of instant messaging  0.25-1MB
1 hour of web browsing  1.5-25MB
Download 100 emails  1-10MB
1 hour Skype call  180MB
1 hour Skype video call  219MB
Download 1 photo  0.05-2MB
Download 1 MP3  3-8MB
Download 1 film trailer (720p)  50-100MB
1 software download  5-800MB
Download 1 film  700MB-1.5GB
Streaming 1 hour of video (standard definition)  100-250MB
Streaming 1 hour of video (high definition)  1-2GB
Streaming 1 hour of audio   60-200MB


Instant messaging, social networking and surfing the web
As you will see from the figures above just being on the web shouldn't eat into your usage allowance by too much, even on the cheaper, low usage plans. And even at the highest estimates on web surfing, you would get 40 hours of surfing on a 0.5GB monthly plan, so that's more than an hour per day.

The reasons for the large range in usage calculations are many: if you're simply surfing basic websites, or chatting simply with text on an instant messenger, your usage will be very low. 

However, many websites automatically load complex add-ons when you visit them, such as streaming audio/video and animations, while many use social networking and instant messaging to exchange images, video clips etc. If you are visiting a lot of sites that download video clips automatically, you should also make sure you're aware of the amount of data use this can incur (see below).

Downloading emails
Don't forget there are two types of email – web-based and software based. If you use a web-based email system such as Hotmail, Yahoo or Gmail, checking your email is just counted as surfing the web (except if you download an attachment – then see below).

If you use a software solution, such as Outlook, then you are downloading all that email to your computer – attachments and all – whether you open them or not. The reason the spread is so large is that there is an estimate of how many, and how large, your attachments will be. This will only really be a concern if you receive a lot of large files in your inbox.

Using Skype with mobile broadband
Our estimate of 150MB for 100 minutes is based on data provided by Skype itself. They claim that when making Skype-Skype calls you'll use around 3MB per minute. If you're calling from Skype to a landline that drops to about 1MB per minute. Video calls consume around 500-600Kbps depending on whether it's to a mobile device or computer. That equates to over 200MB an hour at the very least.

Downloading software
Here as well you will notice quite large differences in the estimates of how big each type of file will be; this quite simply comes down to the huge variance in the size of software packages.

You'll find a vast number of applications will be under 10MB, however software such as anti-virus tools can be much larger, while complex applications like Microsoft Office or the Adobe suites can run up to or over 1GB. This is also true of patches, be it Windows updates or a patch for games, which can easily be hundreds of MB in size.

Images can be tiny, and often have to be if used as an avatar on a social networking site or message board (perhaps only 20K). However, large detailed images in high quality formats can run over 5MB. In a lot of cases though many images will either be small compressed pictures from the web or photos that you upload or download, which are more likely to be a few MB.

Downloading audio
MP3s are the most common way to digitally store music files, with most being 3-8MB in size. The variation comes for two reasons – the longer the song, and the better quality it is saved, the bigger it will be. Most clock in around 1-1.5MB per minute.

Downloading video
This can be really data intensive, so be careful. While a short clip of a song or goal highlights could be as small as 10MB, a full DVD quality film could be as much as 1.5GB or more. HD downloads will be much larger, in the region of 2-3GB or more. A HD movie trailer just a few minutes long can easily exceed 100MB.

Streaming video
Streaming both audio and video is now very popular, but can also be very data intensive. It's tricky to estimate as there are so many video streaming sites, though as a rough guide the BBC says one hour of television from iPlayer will see you downloading anywhere from 50-225MB of data. YouTube uses up about 250MB per hour for a 480p video, the default setting. 

HD content will obviously use a lot more bandwidth. For example, Netflix HD streams can be anywhere from 1GB an hour to over 2GB an hour, so a single movie could run through the entire monthly data allowance for basic mobile broadband packages.

Streaming audio
Audio is less data intensive, but can still add up. Our data usage estimation is based on Spotify as that's currently the most popular audio streaming service.

Spotify offers a variety of quality levels, with the lowest using about 50MB an hour and the highest running to almost 150MB. However you also need to account for the P2P service Spotify uses to bolster its network. Each person running desktop Spotify is also hosting a peer-to-peer service and this can add 10-50MB per hour. You can block the P2P feature using a firewall.

All in Spotify can use 200MB per hour so you could burn through 1GB data in a single working day. To make it last use the lowest quality setting and disable P2P.

What the mobile broadband provider websites say

To give you an idea of how the companies that sell you your mobile broadband products look at data usage, here is a summary of information taken from their sites*:


BT has an array of different packages with numerous data allowances too, but as one typical example, it states that with a pre-pay deal you can use the supplied 1GB of data to download 48 photos, 144 songs, 1 film, 300 emails and enjoy 400 plus browsing minutes.


The EE data calculator is a funky wheel thing that contains pretty good information, although it's a bit on the high side (for example, it suggests that if you just stream "TV shows" on mobile broadband every week you should get a 5GB allowance. That's a bit vague for our liking). 


O2 has an online calculator that offers help in working out what kind of mobile broadband tariff to go for - kind of. As an example, if you’re going to send and receive 'lots' of emails, download songs 'now and then' and also download video clips 'quite a bit', then you’ll only need around 500MB of monthly data usage. However, add on 24 hours of web browsing a week, 5 hours of streaming video clips and lots of app use and it adds up to more like 2GB. It's a bit vague, but better than some!


Orange mobile broadband queries now see you directed directly through to EE. Please see the link to its usage calculator above. 


T-Mobile has a simplistic data calculator that is actually pretty good. For example, it suggests 250-500MB will be enough for a user; "Occasionally checking emails, browsing news sites and seeing what's happening on Facebook."; while someone, "Frequently browsing news sites, checking out Facebook, watching YouTube now and then. Comes with WiFi." would need more like 8GB.


Unfortunately, Three has a pretty useless 'how much data do you need?' calculator on its site. It has scales for email, video, games/TV but none of them actually have any numbers on them, just a scale from "not much" to "loads". Quite how you're meant to gauge that is anyone's guess (answers on a postcard). Luckily, we can give you some good numbers below.


Vodafone has figures on its website that suggest 1GB of data will let you do the following every day: "Read and reply to 200 emails, read 190 BBC news stories and browse 90 mobile web pages." That's all she wrote.

Virgin Media

Virgin Mobile indicates that with their 1GB data allowance you will be able to send 700 emails, download 65 music tracks, download 30 two-minute videos, and browse online for 30 hours. Alternatively, a 3GB data allowance will enable you to send 2,000 emails, download 300 music tracks, download 100 two-minute videos and browse online for 100 hours.

*Data accurate as of January 2013.

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