Hydraulic CALC is a free mobile application designed to provide quick access to various formulas, theories, and coefficients related to hydraulics. The app is specifically tailored for civil engineers working in the field of water supply and sewage systems. The app features a comprehensive list of formulas, including flow section properties, hydraulic mean depth, manning formula, hazen-williams equation, Darcy-Weisbach equation, minor loss coefficient, weir, and orifice formulas. The app also includes hydrology formulas such as the rational method and time of concentration. The formulas are carefully curated to ensure accuracy, but users are advised to double-check for errors. The app is available on Android and comes with a contact email for users to send their feedback and suggestions for future updates.