Roof runoff calculator. Use our Rainwater Drainage Calculator to quickly find runoff flow. Perfect for drainage design and stormwater management. Simple tool to calculate rainwater drainage, runoff, and storm drain size. The tools guide the user step by step allowing fast and simple roof drainage design whilst ensuring full compliance with BS EN12056-3 rainwater drainage design standard. Wondering how much rainwater you could collect off your roof? Use this rainwater harvesting calculator to find the answer. Calculate the amount of water runoff from your roof during rainfall to properly size your gutter system and prevent water damage. Multiply the two figures together to obtain the square footage of your roof. Designed for various surface types, rainfall intensities, roof areas, pavements, and landscapes, it supports planning for retention systems, drainage design, flood management, and hydrology assessments with accurate runoff calculations. Try this rainwater harvesting calculator that helps determine the potential volume of rainwater that can be collected from a catchment area, typically a roof surface. Determine roof runoff volume based on area, rainfall intensity, and duration to optimize your gutter system design. vvg vyxe irxey rzpbgjby tjsdwj xlunwj tkbkmt snrs hyjj sgl