I built Fuel Oil Mix Calculator because I was tired of doing the same math every time I fueled my vintage East German Trabant 601. The app solves a simple but annoying problem: calculating the exact amount of 2-stroke oil needed for a fuel mix. Enter the fuel amount and mixture ratio, or select a saved vehicle, and it gives you the answer instantly. It supports custom ratios, metric and US units, vehicle management, and presets for classics like Trabant 601, Wartburg 353, and MZ ETZ. It is a small practical tool born from real garage life.