FPM to CFM Calculator
Convert air velocity (feet per minute) to airflow volume (cubic feet per minute) with accurate duct area calculations.
Airflow Calculator
Calculate Duct Area
Conversion Formulas
FPM to CFM:
For areas in square inches: CFM = FPM × (Area ÷ 144)
CFM to FPM:
Circular Area:
Where r = diameter ÷ 2
Rectangular Area:
Example Calculations
Results
Enter airflow values to calculate conversion
Complete Guide to FPM to CFM Conversion
An FPM to CFM Calculator converts air velocity into airflow volume. FPM (feet per minute) measures how fast air moves, while CFM (cubic feet per minute) measures how much air flows through a space. Since airflow depends on both speed and size, duct or opening area is required for accurate results.
Why Area Is Important
FPM alone cannot define airflow. The same air speed produces different airflow volumes depending on duct size. This calculator makes area selection simple by offering circular, rectangular, and custom area inputs.
Formula Used in This Calculator
The core formula is:
If the area is entered in square inches:
For reverse calculation:
Example Calculation
Air velocity: 500 FPM
Duct area: 2 ft²
FPM to CFM Example Table
| FPM | Area (ft²) | CFM |
|---|---|---|
| 200 | 1.0 | 200 |
| 400 | 1.5 | 600 |
| 600 | 2.0 | 1200 |
| 800 | 2.5 | 2000 |
| 1000 | 3.0 | 3000 |
Calculator Highlights
- Multiple area units: Supports square feet, inches, and meters
- Shape-based calculations: Built-in circular and rectangular duct area calculation
- Bidirectional conversion: Convert both FPM to CFM and CFM to FPM
- Real-time updates: Calculations update instantly as you type
- User-friendly interface: Works for HVAC professionals and beginners
Summary
This FPM to CFM Calculator delivers accurate airflow results using simple inputs and clear formulas. With multiple unit options, a unique tab layout, and built-in area calculation, it's a reliable tool for HVAC, engineering, and everyday airflow calculations.