Gear Pump Size Calculator
Find the right pump size quickly with a gear pump size calculator. This tool helps you match flow rate, pressure, and efficiency in seconds to avoid oversizing and reduce energy waste.
Pump Displacement & Performance
How to Use a Gear Pump Size Calculator
Follow these simple steps to determine the correct displacement for your gear pump:
- Enter Flow Rate: Input the required flow rate in GPM or LPM. This value depends on your system demand.
- Enter Pump Speed: Add the pump speed in RPM. Check your motor or system specifications.
- Enter Volumetric Efficiency: Use a typical value between 85% and 95%. New pumps typically operate near 90%.
- Enter Pressure (Optional): Input system pressure if required. This helps estimate power and torque needs.
- Click Calculate: The calculator will display the pump displacement and estimated performance.
Tip: Always double-check units before calculating.
Gear Pump Size Calculation Guide
Learn how to calculate gear pump size manually using the standard engineering formula.
Formula:
Step-by-Step Example:
Given: Flow Rate = 60 LPM, Pump Speed = 1500 RPM, Efficiency = 90% (0.90)
1. Multiply flow rate by 1000: 60 × 1000 = 60,000
2. Multiply RPM by efficiency: 1500 × 0.90 = 1,350
3. Divide values: 60,000 ÷ 1,350 = 44.44 cc/rev
Result: Required gear pump size = 44.44 cc/rev. Select a pump close to this displacement value.
Gear Pump Size Conversion Chart
Quick reference values for common gear pump sizes assuming 90% efficiency (where applicable):
| Flow Rate (LPM) | RPM | Efficiency | Pump Size (cc/rev) |
|---|---|---|---|
| 20 | 1000 | 0.90 | 22.22 |
| 40 | 1200 | 0.90 | 37.04 |
| 60 | 1500 | 0.90 | 44.44 |
| 80 | 1800 | 0.85 | 52.29 |
| 100 | 2000 | 0.90 | 55.56 |
Frequently Asked Questions (FAQs)
A gear pump size calculator helps you determine the correct pump displacement based on flow rate, RPM, and efficiency.
Correct sizing ensures proper flow, reduces energy use, and prevents system damage from cavitation or excessive speed.
An oversized pump wastes energy and may cause overheating or system inefficiency as more fluid is bypassed through relief valves.
Use 85%–95%. New pumps typically operate near 90% efficiency. Lower values (80-85%) apply to worn or older pumps.
Yes, but consider fluid viscosity. Thick fluids may reduce volumetric efficiency and require lower shaft speeds.
Higher RPM reduces the required displacement to achieve the same flow. Lower RPM increases the required displacement.
Basic size (displacement) calculation does not require pressure. However, pressure helps estimate power and torque needs.
Use LPM or GPM for flow and RPM for speed. Keep units consistent – for example, use PSI for pressure when using GPM.
Yes. 1 in³/rev is approximately equal to 16.387 cc/rev. The calculator provides both units in the result section.
Yes, for standard conditions. However, always verify results with manufacturer technical data sheets for specific pump models.