Skip to content The FPM to CFM calculator helps you quickly and accurately convert feet per minute to cubic feet per minute, allowing professionals in HVAC, industrial ventilation, and airflow management to measure and optimize air circulation.
Whether you need to convert FPM to CFM for a round duct, calculate FPM to CFM in a rectangular duct, or understand the CFM to FPM formula, this guide covers everything you need.
Key Takeaways
- FPM (Feet Per Minute) measures the linear velocity of airflow.
- CFM (Cubic Feet Per Minute) calculates the volumetric flow rate of air.
- The FPM to CFM formula is:
CFM = FPM × Area (sq ft) - You can use a convert FPM to CFM calculator to simplify calculations.
- CFM vs FPM: CFM represents the volume, while FPM represents the speed.
What is an FPM to CFM Calculator?
An FPM to CFM calculator is a tool that converts feet per minute to cubic feet per minute, essential for:
- HVAC system design and maintenance
- Industrial ventilation planning
- Exhaust system specifications
- Air quality control in commercial spaces
- Duct airflow calculations in rectangular and round ducts
Understanding FPM and CFM
- FPM (Feet Per Minute): Measures the speed of airflow in a given direction.
- CFM (Cubic Feet Per Minute): Measures the total volume of air moved.
How to Convert FPM to CFM?
To convert FPM to CFM, you need the cross-sectional area of the duct:
Formula: CFM=FPM×Area (sq ft)CFM = FPM \times \text{Area (sq ft)}CFM=FPM×Area (sq ft)
Example 1: Round Duct Calculation
Given:
- Air velocity: 1000 FPM
- Duct diameter: 1 ft
Step-by-step calculation:
Area=π×(Diameter/2)^2=0.785 sq ft
CFM=1000×0.785=785 CFM
Example 2: Rectangular Duct Calculation
Given:
- Air velocity: 800 FPM
- Duct size: 2 ft × 1.5 ft
Step-by-step calculation:
Area=2×1.5=3 sq ft
CFM=800×3=2400 CFM
Need a quick answer? Use a convert FPM to CFM calculator for instant results.
How to Calculate FPM?
If you have CFM and duct area, you can find FPM using:
FPM=CFM/Area (sq ft)
Example Calculation
Given:
- Airflow: 1500 CFM
- Duct area: 3 sq ft
Step-by-step calculation:
FPM=1500/3=500 FPM
Use an FPM calculator or a CFM to FPM converter for quick results.
How to Calculate FPM in a Duct?
To calculate FPM in a duct, follow these steps:
- Measure CFM using an anemometer or HVAC system specs.
- Find the area of the duct:
- Rectangular duct: Multiply width × height.
- Circular duct: Use: Area=π×(Diameter2)^2
- Use the formula: FPM=CFM/Area
Example Calculation for a Circular Duct
Given:
- Duct diameter: 2 ft
- Airflow: 800 CFM
Area=π×1^2=3.14 sq ft
FPM=800/3.14≈255 FPM
This method is essential for CFM and FPM calculations in HVAC ductwork.
FPM to CFM Conversion Chart
| FPM (Feet Per Minute) | Duct Size (sq ft) | CFM (Cubic Feet Per Minute) |
|---|---|---|
| 1000 FPM | 2 sq ft | 2000 CFM |
| 800 FPM | 1.5 sq ft | 1200 CFM |
| 500 FPM | 3 sq ft | 1500 CFM |
| 1200 FPM | 2.5 sq ft | 3000 CFM |
Frequently Asked Questions
Why is converting FPM to CFM important?
This conversion is critical for HVAC engineers, industrial designers, and facility managers to ensure efficient airflow and compliance with ventilation standards.
How accurate are FPM to CFM calculations?
They are highly accurate when using precise measurements for air velocity and duct size.
Can I convert CFM back to FPM?
Yes! Use the formula: FPM=CFMAreaFPM = \frac{CFM}{\text{Area}}FPM=AreaCFM
What tools are needed to measure FPM?
An anemometer or velometer measures air velocity in feet per minute.
Conclusion
The FPM to CFM calculator is a valuable tool for HVAC professionals, industrial engineers, and anyone managing airflow systems.
By understanding how to convert feet per minute to CFM, you can improve ventilation, optimize system performance, and ensure compliance with airflow standards.
For instant calculations, use a CFM to FPM converter or a convert FPM to CFM calculator to simplify your work.
