Free Pipe Flow Rate Calculator
Estimate the volumetric flow rate through a pipe given its inside diameter and the velocity of the fluid.
in
ft/s
Flow Rate
48.96 GPM
Flow Rate0.1091 cu ft/s
Flow Rate vs Inside Diameter
Pipe Flow Rate
Q = A x V
Where A is the cross-sectional area of the pipe (pi x r squared) and V is the average fluid velocity. Convert inches to feet before computing the area. Multiply cu ft/s by 448.831 to get gallons per minute.
Example Calculation
A 2-inch inside-diameter pipe with water flowing at 5 ft/s.
- 01Radius in feet = 2 / 2 / 12 = 0.0833 ft
- 02Area = pi x 0.0833 squared = 0.02182 sq ft
- 03Q = 0.02182 x 5 = 0.1091 cu ft/s
- 04GPM = 0.1091 x 448.831 = 48.95 GPM
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