Pump Flow Rate Calculator
Flow, head and hydraulic power.
Enter your values
Enter the flow rate in L/s.
Enter the total head in m.
Enter the pump efficiency in %.
Enter the fluid density in kg/m³.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Motor power required
- 4.04 kW
- Hydraulic power
- 2.83 kW
- Flow
- 43.2 m³/h
- Power in hp
- 5.41
Quick answer
Pump power depends on flow, total head, fluid density and efficiency.
Power = ρ × g × Q × H ÷ efficiency
At a glance
| What it does | Flow, head and hydraulic power. |
|---|---|
| Category | Engineering |
| Inputs needed | Flow rate, Total head, Pump efficiency, Fluid density |
| Main output | Motor power required |
| Formula | Power = ρ × g × Q × H ÷ efficiency |
| Cost | Free — no sign-up, no download |
How to use the Pump Flow Rate Calculator
- 1Enter the required flow rate.
- 2Enter total head including friction losses.
- 3Enter pump efficiency from the curve.
Inputs explained
- Flow rate(L/s)
- Enter the flow rate in L/s.
- Total head(m)
- Enter the total head in m.
- Pump efficiency(%)
- Enter the pump efficiency in %.
- Fluid density(kg/m³)
- Enter the fluid density in kg/m³.
Worked example
Using the values the calculator loads with:
Inputs
- Flow rate12 L/s
- Total head24 m
- Pump efficiency70 %
- Fluid density1000 kg/m³
Results
- Motor power required4.04 kW
- Hydraulic power2.83 kW
- Flow43.2 m³/h
- Power in hp5.41
Frequently asked questions
What is total head?
Static lift plus friction and pressure head, not just the vertical rise.
What efficiency should I use?
60–80% for centrifugal pumps in typical duty.
What do I need to enter into the Pump Flow Rate Calculator?
Just 4 values: flow rate, total head, pump efficiency, fluid density. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Pump Flow Rate Calculator work out the answer?
Pump power depends on flow, total head, fluid density and efficiency. It applies the formula Power = ρ × g × Q × H ÷ efficiency and shows the working so you can check each step by hand.
Is the Pump Flow Rate Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.