Area Drain Sizing Calculator

Size area drains for paved surfaces, courtyards, and loading docks.

Surface area draining to inlet.
sq ft
Design storm intensity.
in/hr
1=flat, 2=curved vane, 3=slotted.

Results

Peak Flow Rate-GPM
Required Grate Area-sq in
Drain Pipe Size-inches
References: Based on storm drain inlet capacity and grate efficiency ratings