Bandwidth is the data that is transferred throughout the network over a specified time - determined by traffic and content.
Each time a user accesses your website, bandwidth is used. While user traffic is the actual amount of visitors on your website; bandwidth is the summary of the data exchanged with the server due to actions of the users.
Live testing is the only way to measure the bandwidth required for new websites. Once the website is launched, our service allows you to monitor the bandwidth usage, so you may determine whether to downgrade or upgrade your existing package to suit your needs.
It is impossible to tell the amount of bandwidth necessary for a new website before making it live. Once it is live, the usage may also not stay the same. Changing themes, adding new features, uploading more content and sheer user volume can affect bandwidth, so it is a good idea to keep a close eye on this to maintain premium optimisation of your website.
Basically; the higher your bandwidth, the more efficient your website will run.