Fluid Power Formulas (2024)



Basic Fluid Power Formulas / Hydraulics / Pneumatics
Variable	Word Formula w/ Units	Simplified Formula
Fluid Pressure - P	(PSI) = Force (Pounds) / Area ( Sq. In.)	P = F / A
Fluid Pressure - P
Fluid Flow Rate - Q	GPM= Flow (Gallons) / Unit Time (Minutes)	Q = V / T
Fluid Power in Horsepower - HP	Horsepower = Pressure (PSIG) × Flow (GPM)/ 1714	HP = PQ / 1714
Actuator Formulas
Variable	Word Formula w/ Units	Simplified Formula
Cylinder Area - A	( Sq. In.) = ? × Radius (inch)²	A = ? × R²
Cylinder Area - A	(Sq. In.) = ? × Diameter (inch)²/ 4	A = ? × D²/ 4
Cylinder Force - F	(Pounds) = Pressure (psi) × Area (sq. in.)	F = P × A
Cylinder Speed - v	(Feet / sec.) = (231 × Flow Rate (gpm))/ (12 × 60 × Area)	v = (0.3208 × gpm) / A
Cylinder Volume Capacity - V	Volume = ? × Radius²× Stroke (In.) / 231	V = ? × R²× L / 231(L = length of stroke)
Cylinder Flow Rate - Q	Volume = 12 × 60 × Velocity (Ft./Sec.) × Net Area(In.)²/ 231	Q = 3.11688 × v × A
Fluid Motor Torque - T	Torque (in. lbs.) = Pressure (psi) × disp. (in.³/ rev.) / 6.2822	T = P × d / 6.2822
	Torque = HP × 63025 / RPM	T = HP × 63025 / n
	Torque = Flow Rate (GPM) × Pressure × 36.77 / RPM	T = 36.77 × Q × P / n
Fluid Motor Speed- n	Speed (RPM) = (231 × GPM) / Disp. (in.)³	n = (231 × GPM) / d
Fluid Motor Horsepower - HP	HP = Torque (in. lbs.) × rpm / 63025	HP = T × n / 63025
Pump Formulas
Variable	Word Formula w/ Units	Simplified Formula
Pump Output Flow - GPM	GPM= (Speed (rpm) × disp. (cu. in.)) / 231	GPM = (n ×d) / 231
Pump Input Horsepower - HP	HP = GPM × Pressure (psi) / 1714 × Efficiency	HP = (Q ×P) / 1714 × E
Pump Efficiency - E	Overall Efficiency = Output HP / Input HP	E_Overall= HP_Out/ HP_{In X 100}
Pump Efficiency - E	Overall Efficiency = Volumetric Eff. × Mechanical Eff.	E_Overall= Eff_Vol.× Eff_Mech.
Pump Volumetric Efficiency - E	Volumetric Efficiency = Actual Flow Rate Output (GPM) / Theoretical Flow Rate Output (GPM) × 100	Eff_Vol.= Q_Act./ Q_Theo.X 100
Pump Mechanical Efficiency - E	Mechanical Efficiency = Theoretical Torque to Drive / Actual Torque to Drive × 100	Eff_Mech= T_Theo./ T_Act.× 100
Pump Displacement - CIPR	Displacement (In.₃/ rev.) = Flow Rate (GPM) × 231 / Pump RPM	CIPR = GPM × 231 / RPM
Pump Torque - T	Torque = Horsepower × 63025 / RPM	T = 63025 × HP / RPM
Pump Torque - T	Torque = Pressure (PSIG) × Pump Displacement (CIPR) / 2?	T = P × CIPR / 6.28