Fan Wind Speed Calculator

The Fan Wind Speed Calculator helps you determine how fast air is moving when blown by a fan. It uses the fan's airflow rate and the size of the opening to calculate wind speed, which is crucial for ventilation, cooling, HVAC system planning, and indoor air quality control.

This tool falls under the Airflow and Ventilation Engineering Calculators category. It’s especially useful in engineering, HVAC design, and energy efficiency analysis, where understanding the airflow velocity helps in making better system choices.

formula of Fan Wind Speed Calculator

Wind Speed (v) = Q / A

Where:

v = Wind speed (in meters per second or feet per minute)
Q = Airflow rate (in m³/s or CFM)
A = Cross-sectional area of airflow (in m² or ft²)

Metric Units:

v (m/s) = Q (m³/s) ÷ A (m²)

Imperial Units:

v (FPM) = Q (CFM) ÷ A (ft²)
Or
v (FPM) = (Q (CFM) × 144) ÷ A (in²)

To calculate area (A) for a circular fan outlet:

A = π × (d / 2)²
Where:
d = diameter of the fan outlet (same unit system as v)

These formulas help calculate how fast air exits or moves across a surface, making it easier to design proper airflow in a space.

Common Wind Speed Reference Table

This reference table helps understand the approximate wind speed values at different airflow rates and outlet sizes.

Fan Diameter (inches)	Outlet Area (ft²)	Airflow Rate (CFM)	Wind Speed (FPM)
10	0.55	1000	1818
12	0.79	1200	1519
16	1.40	2000	1428
20	2.18	2500	1146
24	3.14	3000	955

This table can assist users in making quick checks without performing calculations for each scenario.

Example of Fan Wind Speed Calculator

Let’s say you have a fan with a diameter of 16 inches and it produces 2000 CFM.

First, calculate the area of the fan outlet:

d = 16 in → convert to feet = 1.33 ft
A = π × (1.33 / 2)² ≈ 1.39 ft²

Now apply the formula:
v = Q / A = 2000 CFM / 1.39 ft² ≈ 1439 FPM

This means the wind speed coming out of the fan is about 1439 feet per minute.

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