Expert Verified Pumping Tools Updated 2026

Gear Pump Flow Rate Calculator

Calculate flow quickly and accurately with a gear pump flow rate calculator. This guide helps you understand flow rate, formulas, and real-world usage. Use it to size pumps, improve efficiency, and avoid costly mistakes.

Flow Rate Calculator

in³/rev
RPM
%
Estimated Flow Rate
0.00 GPM

How to Use Gear Pump Flow Rate Calculator

Follow these simple steps to use a gear pump flow rate calculator:

  1. Step 1: Enter Pump Displacement: Input the pump displacement value (cc/rev or in³/rev). You can find this in the pump datasheet.
  2. Step 2: Enter Pump Speed (RPM): Add the operating speed of the pump in revolutions per minute.
  3. Step 3: Enter Efficiency (Optional): Input volumetric efficiency if known (usually 85%–95%). If unsure, use a standard value like 90%.
  4. Step 4: Click Calculate: The calculator will instantly show the flow rate (GPM or LPM).
  5. Step 5: Review Results: Check if the flow rate matches your system requirements.

How to Calculate Gear Pump Flow Rate

Use this basic formula:

Flow Rate = (Displacement × RPM × Efficiency) / Conversion Factor

Common formula (GPM):

Flow Rate (GPM) = (Displacement (in³/rev) × RPM × Efficiency) / 231

Step-by-Step Example

Given:
Displacement = 2.5 in³/rev
RPM = 1500
Efficiency = 90% (0.9)

Step 1: Multiply displacement by RPM
2.5 × 1500 = 3750

Step 2: Multiply by efficiency
3750 × 0.9 = 3375

Step 3: Divide by 231
3375 ÷ 231 = 14.61 GPM

Final Answer:
Flow Rate = 14.61 GPM

Gear Pump Flow Rate Conversion Chart

This chart helps convert common flow rate units:

Unit Conversion Value
1 GPM 3.785 LPM
1 LPM 0.264 GPM
1 m³/hr 4.402 GPM
1 GPM 0.227 m³/hr
1 cc/rev 0.061 in³/rev
1 in³/rev 16.387 cc/rev

Tip: Always match units before calculating to avoid errors.

FAQs About Gear Pump Flow Rate Calculator

A gear pump flow rate calculator estimates the fluid output based on displacement, speed, and efficiency.

Efficiency accounts for internal leakage and losses. It ensures accurate results.

Yes, but results will be ideal. Real-world flow will be lower.

GPM (gallons per minute) and LPM (liters per minute) are most common.

It is highly accurate if you use correct input values and efficiency.

Key factors include: Pump speed (RPM), Displacement size, Fluid viscosity, and Internal leakage.

Yes, it works for most external and internal gear pumps.

Increase RPM or use a pump with larger displacement.

It remains consistent under stable conditions but varies with load and wear.

Use 85%–95% depending on pump condition and manufacturer data.

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