CFM to FPS Calculator

The CFM to FPS converter is a useful tool. You can easily determine feet per second (FPS) from cubic feet per minute (CFM), or to calculate CFM and cross-sectional area based on known inputs.

This calculator offer two mode for conversion. The basic mode is a simple tool for airflow calculation and advance tool provides more complex setups involving air density and mass flow rate.

Simply select the desired mode, enter the known values, and press “Calculate” for immediate results.

Convert CFM ↔ FPS

Contents

• 1 Convert CFM ↔ FPS
• 2 How to Calculate FPS from CFM
• 3 Example
  • 3.1 💡 Bonus Tip
• 4 Summary
• 5 FAQs

Basic Advanced

CFM:

Area (ft²):

FPS:

Leave one field empty

Density (lb/ft³):

Mass Flow (lb/min):

Area (ft²):

Velocity (ft/s):

Calculate

Reset

How to Calculate FPS from CFM

The basic formula to calculate air velocity (FPS) from CFM and cross-sectional area is:

$$\text{FPS} = \frac{\text{CFM}}{\text{Area} \times 60}$$

Advance mode calculation involving air density and mass flow rate, the formula is:

$$\text{FPS} = \frac{\text{Mass Flow Rate}}{\text{Density} \times \text{Area}}$$

Example

For example, you want to design a commercial HVAC system that needs to supply 5000 CFM of air through a 4 ft² duct. Use the formula, you can easily determine that the airflow velocity will be 20.83 FPS, It will ensure you that the duct size is appropriate to minimize air resistance and energy loss.

• CFM: 3000
• Cross-Sectional Area: 2.5 ft²

Basic Mode:

• Mass Flow Rate: 500 lb/min
• Air Density: 0.075 lb/ft³
• Cross-Sectional Area: 3 ft²

💡 Bonus Tip

Proper airflow velocity is most important in ventilation, exhaust systems, and for industrial airflow control. For more precise airflow analysis always use the advance mode for more.

Summary

Mode	Purpose
Basic Mode	Converts CFM to FPS using cross-sectional area only
Advanced Mode	Uses air density and mass flow rate for detailed airflow calculations
Key Formula (Basic)	FPS = CFM ÷ (Area × 60)
Key Formula (Advanced)	FPS = Mass Flow Rate ÷ (Density × Area)
Best Use Cases	Ventilation planning, duct sizing, HVAC and industrial airflow setup

FAQs

1. What does this calculator do?
It converts airflow (CFM) into velocity (FPS).

2. What values are needed?
CFM and area for basic mode; add density and mass flow for advanced mode.

3. Can I reverse the calculation?
Yes, you can also find CFM or area if FPS is known.

4. Who is this tool for?
HVAC pros, system designers, and industrial planners.

5. Why use advanced mode?
It gives more accurate results by factoring in air properties.