CFM to MPH Calculator

Do you want to know how fast air is moving when you measure it in CFM? Our CFM to MPH calculator is designed to make it easy for you to convert air flow rate (CFM) into air velocity (MPH) in just seconds. Whether you're working with HVAC systems, fans, or industrial ventilation, this tool will help you get the job done without any complicated math.

Understanding the relationship between cubic feet per minute (CFM) and miles per hour (MPH) helps you determine how fast air is traveling through a given space. With our calculator, you don't need to be an engineer or a mathematician to figure it out.

How Does CFM Relate to MPH?

CFM (Cubic Feet per Minute) measures the volume of air flowing per minute. MPH (Miles per Hour) measures the speed at which the air travels.

To convert CFM to MPH, you need to know the cross-sectional area of the duct, pipe, or opening the air is flowing through. This is because you’re converting from a volume (CFM) to a distance (MPH), and area helps bridge that gap.

The basic concept is:

• More air in a smaller space = faster speed (higher MPH)
• Less air in a larger space = slower speed (lower MPH)

CFM to MPH Calculation Formula

The formula to convert CFM to MPH is:

MPH = (CFM / Area in ft²) × 0.0113636

Where:

• CFM is the flow rate in cubic feet per minute
• Area is the cross-sectional area in square feet
• 0.0113636 is the conversion factor that accounts for time and distance (60 minutes per hour divided by 5,280 feet per mile)

If you only have the diameter of a circular duct, calculate the area first using:

Area = π × (Diameter ÷ 2)²

Then plug the area into the main formula to find the MPH.

How to Use the CFM to MPH Calculator

Using our online calculator is very simple and beginner-friendly. Here’s how it works:

1. Enter the air flow rate (CFM) into the first field.
2. Enter either the cross-sectional area or the diameter of the duct.
3. Choose the appropriate unit (feet, meters, inches, etc.).
4. Select the desired output unit (MPH, FPM, FPS, m/s, km/h, knots).
5. Click Calculate, and the result will be displayed instantly with step-by-step breakdowns.

Our tool also auto-calculates area if you provide the diameter, saving you time and effort.

Example Calculations

What is 1 CFM equal to in MPH?

Assume area = 1 square foot:

MPH = (1 / 1) × 0.0113636 = 0.0114 MPH

How many MPH is 600 CFM?

Assume area = 2 square feet:

MPH = (600 / 2) × 0.0113636 = 300 × 0.0113636 = 3.4091 MPH

How fast is 1000 CFM?

Assume area = 3 square feet:

MPH = (1000 / 3) × 0.0113636 ≈ 3.7879 MPH

These examples show how quickly airflow translates into linear speed based on the size of the outlet.

Final Verdict

The CFM to MPH calculator is a must-have tool for HVAC technicians, engineers, and anyone working with air movement systems. It simplifies a technical calculation into a user-friendly experience. You don’t have to memorize formulas or convert units manually our tool does it all for you.

With support for various input and output units, it’s more than just a CFM to MPH converter. You can also get results in feet per second (FPS), meters per second (m/s), kilometers per hour (km/h), and more. Whether you're adjusting fan speeds or designing ductwork, this calculator can make your work more accurate and efficient.

FAQs

What is 1 CFM equal to?

1 CFM is the volume of air flowing at 1 cubic foot per minute. In terms of speed (MPH), it depends on the area it's flowing through. If the area is 1 square foot, then 1 CFM equals 0.0114 MPH.

How do you convert CFM to MPH?

Use this formula:

MPH = (CFM / Area in ft²) × 0.0113636

This converts air flow into speed by factoring in time and distance.

How many MPH is 600 CFM?

If the area is 2 ft²:

MPH = (600 / 2) × 0.0113636 = 3.41 MPH

How fast is 1000 CFM?

With a 3 ft² duct area:

MPH ≈ 3.79 MPH

Is this calculator accurate?

Yes, it uses proven physical formulas and standard unit conversions to ensure accuracy. Just make sure you input correct values for CFM and area or diameter.