A handy iPhone app for calculating the correct amount of oil required to add to your fuel for your desired mix ratio.
The "Oil Ratio" iPhone app is now available on the App Store.
It's incredibly simple to use, and gives you the choice of metric (litres) or imperial (US gallons) settings. There is no keyboard required with all options controlled by sliders. Also to make it easy to get the exact figure you need there is also the + and - buttons to fine tune your requirements.
Click here to go to the app store for more info.