Ratioo is an OS X app that will help marketeers and designers to quickly calculate sizes or aspect ratio's. Example: As a visual designer you need to create a little visual inside of a UI which gets a maximum width of 320px, then you decide you want it to have a 16:10 ratio so you press a shortcut and quickly enter the ratio and enter 320 and Ratioo will show you which height you should give you visual to let it have a 16:10 ratio. Sounds great right?
via BetaList http://bitly.com/1TtSKYG
by Robert Hughey (Google+)