A download allowance refers to how much internet usage you are allowed in a given period.
Your internet service provider (ISP) will set a download limit for the package you are on, and if you go over that could be charged, usually on a per-GB basis. This does not apply if you are on an unlimited data package, which many ISPs have shifted to.
File sizes are measured in megabytes (MB) or gigabytes (GB), while speeds are measured in megabits per second (Mbps). For more information, read our guide to bits and bytes.
Different amounts of data are downloaded depending on the task, but on the whole, most plain text (like e-mails and websites) use tiny amounts, whereas gaming, video and music will easily — and quickly — cut through an allowance.
For example, if you have a 15GB limit and you want to download a Blu-ray movie that's 8GB, that's over half of your monthly allowance down in one go.
Average broadband download sizes
- 20KB — text e-mails sent and received
- 50KB — a single page on a website
- 3MB — a song
- 3MB — a three-minute video clip
- 400MB — a standard definition film
GB, MB and KB conversions
Since data allowances are measured in GB, you'll need to know the conversion rate between the different sizes:
1GB = 1024MB 1MB = 1024KB
The uSwitch guide to bits and bytes has a lot more information on converting file sizes.
One day on a 3GB package:
2.4MB — 50 text emails sent and received
10MB — 200 website pages
50MB — 10 songs
= 62.4MB or around three hours online.
These are just estimated values. In practice, it's hard to know how much you are going to use until you start downloading and browsing. One way to keep an eye on your usage and avoid overage fees is to use a program that monitors the amount of data you are using.
The good news is that the majority broadband packages currently on the market advertise unlimited downloads.
While this looks like the best deal going, it's important to read the small print. If you study the contract terms closely, you'll find that most (if not all) unlimited broadband packages are subject to fair usage policies.
A fair usage policy stops any one user from using up the majority of bandwidth by limiting their speeds at peak hours of the day. Often broadband providers will notify heavy users by phone or e-mail to warn them that speeds will be curtailed at certain times.
These policies mostly impact those who use peer-to-peer (or P2P) software, as well as online gamers and people who stream large volumes of songs and films.
Check out unlimited broadband packages now if you want to avoid data overages.
One type of broadband that is still subject to strict data allowances is mobile broadband.
Download allowances on many mobile broadband packages are a lot lower than on home broadband packages. For this reason, mobile broadband is less suitable for users who watch or download large amounts of video and music.
If you think you're going to make extensive use of your dongle, it's a good idea to choose one of the many mobile broadband products with a high monthly download limit and to choose a provider that also offers free use of their Wi-Fi hotspots.
Exceeding the download limits
Exceeding the download allowance of your broadband provider can incur a cost from some ISPs. Such costs are detailed in the terms and conditions of your contract. Other ISPs will not charge extra for extra downloads, but they may curb the speed of your connection.