⚙ Hydraulic Pump Torque Calculator
Pressure & displacement to required drive torque
Results
Required Torque
—
lb·ft
Torque (alternate unit)
—
lb·in
Formulas Used
Imperial: T (lb·in) = [P (psi) × D (in³/rev)] / (2π × η)
T (lb·ft) = T (lb·in) / 12
Power (hp) = T (lb·ft) × N (rpm) / 5252
Metric: T (N·m) = [P (bar) × D (cc/rev)] / (20π × η)
Power (kW) = T (N·m) × N (rpm) × 2π / 60000
η = overall pump efficiency (mechanical × volumetric). Typical range: 0.80–0.95.
Theoretical torque uses η = 1.0; actual torque divides by η to account for losses.
Worked Example — Imperial
| Parameter | Value |
|---|---|
| System Pressure | 3,000 PSI |
| Pump Displacement | 2.44 in³/rev |
| Overall Efficiency | 90% (0.90) |
| Pump Speed | 1,800 RPM |
T = (3000 × 2.44) / (2π × 0.90) = 7320 / 5.655 = 1,294 lb·in = 107.8 lb·ft
Power = 107.8 × 1800 / 5252 = 36.9 hp
Power = 107.8 × 1800 / 5252 = 36.9 hp
Worked Example — Metric
| Parameter | Value |
|---|---|
| System Pressure | 207 bar |
| Pump Displacement | 40 cc/rev |
| Overall Efficiency | 90% (0.90) |
| Pump Speed | 1,800 RPM |
T = (207 × 40) / (20π × 0.90) = 8280 / 56.55 = 146.4 N·m
Power = 146.4 × 1800 × 2π / 60000 = 27.6 kW
Power = 146.4 × 1800 × 2π / 60000 = 27.6 kW