Pump Flow Rate Calculator
Calculate the volumetric flow rate of a pump based on input power, pump efficiency, fluid density, and total head.
Fill in all fields and click Calculate.
Formula
Q = (P × η) / (ρ × g × H)
- Q — Volumetric flow rate (m³/s)
- P — Shaft input power (W)
- η — Overall pump efficiency (dimensionless, 0–1)
- ρ — Fluid density (kg/m³)
- g — Gravitational acceleration = 9.80665 m/s²
- H — Total dynamic head (m)
Rearranged from the pump power equation: P = (ρ × g × H × Q) / η
Assumptions & References
- Gravitational acceleration is taken as the standard value 9.80665 m/s².
- Efficiency (η) is the overall pump efficiency, combining hydraulic, volumetric, and mechanical losses.
- The fluid is assumed incompressible and Newtonian (valid for water, light oils, etc.).
- Total dynamic head (H) includes static head, velocity head, and friction/minor losses in the system.
- For water at 20 °C, use ρ = 998 kg/m³; for seawater ≈ 1025 kg/m³.
- Reference: Munson, Young & Okiishi, Fundamentals of Fluid Mechanics, 8th ed., §14.2.
- Reference: Kaplan & Sadik, Pump Handbook, 4th ed., McGraw-Hill.