PipeMAC Manning Gravity Capacity Calculator

PipeMAC — storm pipe gravity-flow capacity calculator (Manning's equation)

1Pipe & Flow Parameters

Slope Spipe gradient
1.00%
0.25%10%
Size Dinside diameter · snaps to stock sizes
24in
18 in84 in
Flow Qfull-flow capacity
45cfs
5 cfs200 cfs

2Result

Full-flow capacity — Q —
Full-flow velocity
—ft/s
Full capacity
—cfs
Calculation audit
Q = (1.486/n)·A·R^(2/3)·S^(1/2)  |  A = πD²/4  |  R = D/4  (A, R, D in ft)