Expert Verified Pump Tools Updated 2026

Gear Pump Volume Calculator

Calculate fluid displacement quickly with a gear pump volume calculator. This tool helps you determine pump output based on dimensions and speed. Use it to improve system design, efficiency, and performance instantly.

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IN OUT GEAR PUMP VOLUME CALCULATOR
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Volume & Flow Rate Converter

mm
mm
mm
RPM
%

How to Use Gear Pump Volume Calculator

Follow these simple steps to use the gear pump volume calculator effectively:

  1. 1
    Enter Gear Dimensions: Input gear diameter, width, and tooth size (inner/root diameter). Ensure all values use consistent units (mm).
  2. 2
    Input Rotational Speed (RPM): Enter the pump speed in revolutions per minute. Use actual operating speed for accurate results.
  3. 3
    Enter Volumetric Efficiency: Add efficiency (usually 85%–95%). This improves real-world accuracy.
  4. 4
    Click Calculate: The calculator will instantly show Volume per revolution and Flow rate (L/min or GPM).
  5. 5
    Analyze Results: Use the output to select pump size, optimize system flow, and prevent overloading.

Conversion / Calculation Guide

How to calculate gear pump volume manually:

Basic Formula

Volume per Revolution = Displacement of Gear Teeth × Number of Cavities

Simplified Engineering Formula

Q = V × N

Where:

  • Q = Flow rate (cm³/min or L/min)
  • V = Volume per revolution (cm³/rev)
  • N = Speed (RPM)

Step-by-Step Example

Given: Volume per revolution (V) = 25 cm³/rev, Speed (N) = 1500 RPM.

Step 1: Multiply V × N
Q = 25 × 1500

Step 2: Calculate
Q = 37,500 cm³/min

Step 3: Convert to Liters
37,500 cm³ ÷ 1000 = 37.5 L/min

Final Answer: Flow Rate = 37.5 L/min

Note: Always adjust for efficiency losses. Actual output = Theoretical output × Efficiency.

Gear Pump Volume Conversion Chart

Common Gear Pump Volume Conversions at various speeds:

cm³/rev L/min @ 1000 RPM L/min @ 1500 RPM GPM @ 1500 RPM
5 5 7.5 1.98
10 10 15 3.96
20 20 30 7.93
25 25 37.5 9.91
50 50 75 19.81
75 75 112.5 29.72
100 100 150 39.63
Conversion Tips: 1 Liter = 1000 cm³ | 1 GPM ≈ 3.785 L/min

Frequently Asked Questions (FAQs)

The volume of a gear pump, also known as displacement, is calculated by determining the internal cavity space between the gear teeth and the housing. This fixed volume dictates how much fluid is physically pushed through the pump's outlet port during one complete revolution of the shaft.

In a gear pump, volume usually refers to the internal displacement per revolution. Capacity, on the other hand, describes the total flow rate of the pump over time, such as gallons per minute. Capacity is determined by multiplying the pump's specific volume by its rotational speed.

The width of the gears directly affects the pump's internal volume. Wider gears create larger cavities between the teeth, which allows the pump to carry a significantly greater volume of fluid with each revolution, effectively increasing the displacement and overall output flow rate.

To convert pump volume to GPM, multiply the displacement volume in cubic inches per revolution by the pump's rotational speed in RPM. Then, divide the resulting total by 231, because there are 231 cubic inches in a single gallon. This provides the theoretical gallons per minute output.

A gear pump's effective volume can be reduced by internal slip or leakage, which increases as system pressure rises. Wear and tear on the gear teeth or the housing cavity also increases internal clearances, allowing more fluid to bypass and thereby reducing the actual pumped volume.

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