Gutter Downspout Calculator

    Size downspouts for roof area

    sq ft
    in/hr

    公式

    Flow = Roof Area × Rainfall / 96.23

    Each downspout handles a maximum flow rate.

    示例

    1500 sq ft roof, 4 in/hr

    2-3 downspouts needed.

    常见问题

    关于 Gutter Downspout

    Size downspouts for your roof drainage area.