Pipe Diameter to Flow Rate Calculator Pipe Diameter to Flow Rate Calculator Calculate volumetric flow rate through circular pipes Pipe Diameter Millimeters (mm) Centimeters (cm) Inches Fluid Velocity Meters/second Feet/second Display Flow Rate In Liters/second Cubic meters/hour Gallons/minute (US) Cubic feet/minute System Efficiency (%) Volumetric Flow Rate 0 Pipe Area 0 Velocity 0 Calculate Download PDF