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, 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.
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 broadband. If you use 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 go over a 3GB monthly limit unless they decide to watch a lot of streamed content (see below) or download massive work files. 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 5GB 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.
Broadband usage calculator
As already noted above these are rough estimates based on information gathered from a variety of sources including a variety of 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 7-50MB
1 software download 5-800MB
Download 1 film 700MB-1.5GB
Streaming 1 hour of video (standard definition)50-500MB
Streaming 1 hour of video (high definition) 1-2GB
Streaming 1 hour of audio 50-150MB
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. 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.
he 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 size.
You'll find a vast number of applications will be under 10MB, however software packages 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 be hundreds of MB in size.
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. 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 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 or more. HD downloads will be much larger, in the region of 2-3GB or more.
Streaming audio and 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.
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.
Audio is 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!
