Opera has unveiled the latest versions of its mobile browser, Opera Mini 6.5 and Opera Mobile 11.5, which now allow web users to see how much data they are using.

The browsers, which are initially only available for devices running Google Android, feature a Data Usage function that can be accessed from the Help Menu. By opening Data Usage, web users can see just how much data they have used in Megabytes (MB) allowing them to work out how much they've spent if they don't have a data allowance included in their mobile deal or if they're abroad and using data roaming which costs extra.

Furthermore, the function also shows how much data has been saved by using Opera Turbo, the browser developers compression technology that that compresses the bandwidth of text and data files on websites by up to 80 percent, which not only ensures the user's cost is reduced but also ensures pages load faster. Opera Turbo remains switched on in Opera Mini. However through the same Data Usage function, Opera Mobile users have the ability to switch Opera Turbo on or off.

"Have it on for a month and they'll be literally Gigabytes of savings," said Christen Krough, Opera's chief development officer, adding "there's never any chequerboard" on the browsers referring to how smooth the scrolling is.

Furthermore, both Opera Mini 6.5 and Opera Mobile 11.5 benefit from several "under the hood" improvements including an updated Opera Presto rendering engine, improved network performance, HTML5 micro data and smaller JavaScript engine memory usage.

The browsers, which were demoed for the first time at Opera's Up North Web conference, which took place in Oslo this week and also offered a first-look at Opera 12 - the next iteration of the developer's desktop browser - also benefit from a bookmark import function and Speed Dials – the developer's take on favourites which bring one-click access to a user's favourites sites straight to the browser's home screen.

Those using Opera Mobile on Google Android version 3.0, also dubbed Honeycomb, which is dedicated for use of tablet PCs, will also benefit from support for online video.

"A lot of people don't realise how much money they can save on data traffic, people naturally want an easy way to measure how much data they use," said Lars Boilesen, CEO, Opera Software. "Now, Opera Mini and Opera Mobile will show exactly how much data you save by using our cloud-assisted technology."

Opera Mini 6.5 and Opera Mobile 11.5 for Android are available for free in the Android Market or from Opera's dedicated mobile site.