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 etc, with one of the key areas being usage allowance.

The most generous deals currently offer 15GB of data per month, while the more frugal amongst you can take deals as low as 0.5GB (about 500MB) per month, or take a pay as you go (PAYG) deal where you pay either per day, or per GB. But what can you get for your gigabyte?

Firstly, its 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, remember that the below is only a rough guide - files are not created equal! The information below can be used as a guide to how large files might be, but you should be very careful and keep a close watch on your usage. And 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!

Also, 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 used as a back up for their fixed-line or business connection: they use the service with a laptop to browse the web and download emails when out of the office or on holiday, and not so much 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. Make sure you 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 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 for exceeding your limit

The cost of going over your usage limit can vary dramatically between providers on monthly contracts. T-Mobile will not charge you for exceeding your monthly limit, but if you continue to abuse the service it will restrict your usage. O2 charges £0.20 per MB, 3 Mobile charges £0.10 per MB, while Vodafone charges £15 per extra GB you use (less than £0.02 per MB). Orange Broadband also charges less than £0.02 per MB on 18-month deals, but around £0.05 per MB on rolling monthly contracts.

Mobile broadband usage calculator

As already noted above, these are rough estimates based on the information given on the sites of the mobile broadband providers themselves. Please read the notes below the table for more detailed descriptions that will help explain the variations in estimates.

Instant messaging, social networking and surfing the web
As you will see from the figures above, just being online shouldn't eat into your usage allowance by too much, even on the cheaper, low usage plans. 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 Googlemail, 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.

Downloading images, MP3s, films and 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 quality, size and/or length.

Images
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 be over 5MB. However, most images will either be small compressed pictures from the web or photos that you upload or download, which are more likely to be up to around 2MB.

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 are currently around 1-1.5MB per minute.

Downloading video
This can be a 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.

Streaming audio and video
Streaming both audio and video is now very popular, but can also be very data intensive. It is estimated that streaming one-hour of low quality television from the BBC iPlayer will see you downloading almost 250MB of data, while watching in higher quality is estimated at 300+MB per hour. High definition and DVD quality streaming will be even higher.

Audio is obviously less data intensive, but can still add up. Spotify, for example, suggests it accounts for 256Kb - this means, in data terms, that you will be downloading around 100MB of data per hour. This can soon add up!

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
With 1GB of usage you can download 48 photos, 144 songs, 1 film, 300 emails and have +400 browsing minutes. However, it doesn't say if this is per item, or cumulative - useful!

O2
Only gives a couple of 3GB examples. According to O2, 3GB of data as a monthly bundled allowance is roughly enough to do the following:
I mainly email & browse - Hours spent browsing daily 2; Emails sent & received daily 125; Music downloads per month 25; Video downloads per month 45 mins; Software updates or downloads per month 2.
I do a lot of downloading - Hours spent browsing daily 1; Emails sent & received daily 20; Music downloads per month 25; Video downloads per month 2 hours; Software updates or downloads per month 2.

Orange
100 emails without attachment = 1MB
3 emails with attachment = 1MB
1 email with photo attachment = 1MB
1 hour spent on IM = 1MB
1 hour web browsing = 20MB
downloading one 3-minute MP3 = 4MB
downloading one 10-minute video = 40MB
downloading one film trailer = 10MB

T-Mobile
Nothing at all - we even asked in their live chat...

3
100 emails = 2.4MB
1 hour web browsing = 26MB
1 hour on IM = 0.25MB
Document = 1.5MB
One photo = 1MB
game or software program = 800MB
One four-minute MP3 = 8MB
film trailer (4 min) = 50MB

Vodafone
1 hour web browsing = 10MB
100 emails = 6MB
Document (?) download = 3MB
One MP3 = 8MB
one photo = 2MB
one movie = 1GB
software program = 210MB

Virgin Media
100 emails = 9MB
1 hour web browsing = 1.4MB
1 hour on IM= 0.6MB
Document = 0.1MB
One photo = 0.07MB
Software program = 70MB
One MP3 = 3MB
Downloading one film trailer = 7MB

*Data accurate as of August 2009.