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ENGINEERING TOOL

Air Compressor CFM Calculator

Estimate air compressor flow or receiver tank fill time from tank volume, pressure rise and delivered airflow.

Air Compressor CFM Calculator

FREE ONLINE TOOL
Formula and assumptions

Free-air volume (L) ≈ tank volume (L) × pressure increase (bar); fill time (min) ≈ free-air volume ÷ delivered flow (L/min).

Estimate assumes steady flow and an idealized pressure rise. Enter delivered FAD/SCFM, not piston displacement. Actual performance varies with pressure, temperature, leaks and duty cycle.

A 50 L receiver rising by 2 bar needs about 100 L of free air; at 150 L/min delivered flow, idealized fill time is 0.67 minutes.

STEP BY STEP

How to use air compressor cfm calculator

  1. Check the input units and assumptions.
  2. Review the result and example.

IN PRACTICE

Example

A 50 L tank rising from 6 to 8 bar gauge needs about 100 L of free air. At 150 L/min delivered flow, idealized fill time is 0.67 minutes.

GOOD TO KNOW

Which airflow rating should I enter?

Approximate free-air volume = tank volume × gauge-pressure increase. Fill time = free-air volume ÷ delivered airflow. Use a delivered-flow rating at the operating pressure; displacement ratings can overstate real output.

Practical guides

How to Calculate Air Tank Fill Time: Formula and Example →

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