How to Calculate CFM from FPM

The FPM to CFM Calculator converts air velocity in feet per minute (FPM) to cubic feet per minute (CFM) based on the cross-sectional area. The formula is:

Where the area is converted to square feet from various units.

Where:

• \( CFM \): Cubic feet per minute (airflow rate).
• \( FPM \): Air velocity in feet per minute.
• \( Area \): Cross-sectional area, converted to square feet (e.g., 1 sq ft, 1/144 sq in, 1/929.0304 sq cm, 10.7639 sq m, 9 sq yd).

Enter the air velocity (FPM), area, and select the area unit to calculate the CFM.

Using the FPM to CFM Calculator

This calculator is useful for HVAC and ventilation system design to determine airflow rates.

Input the air velocity in feet per minute (FPM), the area, and select the area unit. The calculator outputs the airflow in cubic feet per minute (CFM).

Example: For an air velocity of 500 FPM and an area of 288 sq in.

1. Air Velocity: \( 500 \, \text{FPM} \)
2. Area: \( 288 \, \text{sq in} = 2 \, \text{sq ft} \) (since 1 sq ft = 144 sq in)
3. Calculation: \( CFM = 500 \times 2 = 1000 \, \text{CFM} \)
4. Result: \( 1000 \, \text{CFM} \)

Use this tool for airflow calculations in duct systems.

Common FAQ

Below are frequently asked questions about FPM to CFM calculations:

• Q: What is FPM?
  A: FPM stands for feet per minute, measuring air velocity.
• Q: What is CFM?
  A: CFM stands for cubic feet per minute, measuring airflow volume.
• Q: How accurate is this calculator?
  A: It provides precise results based on the formula and unit conversions, rounded to 3 decimal places.
• Q: Can negative values be used?
  A: No, FPM and area must be positive; invalid inputs leave the result blank.
• Q: What if the area is irregular?
  A: Use the average cross-sectional area of the duct in the selected unit.