Hydraulic Pump Flow & Power Calculator

Compute hydraulic pump delivery flow (GPM & L/min), electric motor drive horsepower (HP & kW), and input shaft torque across gear, vane, and piston pumps.

Displacement & Speed

Displacement (cu in / rev):

Metric (cc / rev):

Drive Speed N (RPM):

Operating Pressure (psi):

Pump Type & Efficiency

Pump Type & Typical Efficiencies:

Volumetric Eff (%):

Mechanical Eff (%):

Pump Delivery & Power Sizing

Required Electric Motor Power

-- HP

-- kW motor nameplate

Actual Delivery Flow

-- GPM

-- L/min

Drive Shaft Torque

-- ft-lbs

-- in-lbs torque

Theoretical Flow (Zero Leakage): -- GPM

Hydraulic Fluid Horsepower: -- HP

Overall Pump Efficiency: -- %

The 1714 constant governs hydraulic horsepower: HP = (GPM × PSI) / (1714 × Overall Efficiency).

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Frequently Asked Questions

What is the 1714 constant in hydraulic horsepower calculations?

The constant 1714 derives from unit conversions: 1 horsepower = 33,000 ft-lb/min. Since 1 gallon = 231 cubic inches, 1 GPM at 1 psi equals 231 in-lb/min of work = 19.25 ft-lb/min. Dividing 33,000 by 19.25 yields exactly 1714.28.

What is the difference between volumetric and mechanical efficiency in pumps?

Volumetric efficiency represents internal fluid slip/leakage past rotating pistons, gears, or vanes. Mechanical efficiency represents torque lost to mechanical friction in bearings, shaft seals, and churning of viscous oil. Overall efficiency is their product: η_overall = η_vol × η_mech.

Why do bent-axis and axial piston pumps have the highest efficiency at 3,000+ psi?

Piston pumps maintain ultra-precise metal-to-metal clearances sealed by hydrostatic hydrodynamic oil films on the valve plate and swashplate, limiting slip to under 4% even at 5,000 psi, whereas gear pump teeth deflect and slip heavily above 2,500 psi.