IES
Mechanical Engineering2D

Pump Selection Calculator

Estimate pump type selection based on flow rate, head, and fluid properties for preliminary engineering.

Inputs
Enter your values below

100 m³/h ≈ 0.028 m³/s

Water ≈ 0.001 Pa·s

Result
Pump Type Index (higher = centrifugal favored)
—
Enter values and click Calculate
Loading visualization…
Formula
flow × √(head)

Pump selection index = Q√H. Low index (<0.1) = high head/low flow → PD or multi-stage centrifugal. High index (>0.5) = high flow/low head → single-stage centrifugal or axial.

Introduction

Get a preliminary indication of pump type based on specific speed and viscosity. Low flow/high head favors positive displacement; high flow/medium head favors centrifugal; high viscosity favors rotary PD or gear pumps.

How This Calculator Works

Pump selection index = Q√H. Low index (<0.1) = high head/low flow → PD or multi-stage centrifugal. High index (>0.5) = high flow/low head → single-stage centrifugal or axial.

Step-by-step process:

  1. Enter your input values in the calculator above
  2. The engine converts all inputs to SI base units (meters, kg, Pa)
  3. The formula is evaluated: flow * sqrt(head)
  4. Result is formatted with the appropriate unit and precision

Calculation Example

Pump type index based on flow/head ratio: low index (<2) suggests positive displacement, high (>20) suggests centrifugal. This is a simplified guidance only.

Inputs: flow=0.028, head=50, viscosity=0.001
Result: 0.2

Unit Conversion for Pump Selection

**Head units**

- 1 m = 3.28084 ft

- 1 ft = 0.3048 m

**Flow units**

- 1 m³/h = 0.2778 L/s = 4.403 US gpm

- 1 US gpm = 0.2271 m³/h

**Power units**

- 1 kW = 1.341 hp

- 1 hp = 0.7457 kW

**NPSH units**

- 1 m = 3.28084 ft

Pump selection matches the duty point (flow, head) to a manufacturer curve. Convert the duty point and NPSH requirement to the same unit system as the curve before selecting.

Engineering Applications

  • •Pump type selection
  • •FEED studies
  • •Budget estimating
  • •Vendor inquiry preparation

Frequently Asked Questions

When to use positive displacement pumps?

PD pumps for: high viscosity (>500 cP), high pressure/low flow, precise metering, shear-sensitive fluids, or self-priming needs.

What is specific speed?

Specific speed Ns characterizes pump geometry: high Ns (>100) = axial/propeller; medium (30-100) = mixed flow; low (<30) = radial/centrifugal; very low = multi-stage or PD.

How do I convert units when comparing pump curves?

Convert head: 1 m = 3.28084 ft. Flow: 1 m³/h = 4.403 gpm. Power: 1 kW = 1.341 hp. NPSH: 1 m = 3.28084 ft. Use one consistent unit system across the entire selection to avoid curve-matching errors.

Related Calculators

Pump Sizing CalculatorPump Power CalculatorPump Efficiency CalculatorPump Flow CalculatorPump Head CalculatorPump Energy Cost CalculatorPump Affinity Law CalculatorPipe Flow CalculatorFlow Rate CalculatorPressure Drop Calculator (Darcy-Weisbach)Reynolds Number Calculator

Need engineering design support?

Our engineering team validates results like these with full multi-disciplinary design review. Beyond the Pump Selection Calculator, we deliver build-ready engineering.

  • Industrial Building Design
  • Structural Optimization
  • HVAC & MEP Engineering
  • Chemical & Energy Projects
Request Engineering Assessment
Engineering Disclaimer: Calculations are for reference and educational purposes only. Always verify results independently for engineering design. See full disclaimer.
Reviewed by: Industrial Engineering Team
References: ASME B31.3, ASTM A36, Perry's Chemical Engineers' Handbook