Wind Speed to PSI Calculator
Calculate the basic wind pressure produced by a given wind speed and convert the result from pounds per square foot (PSF) to pounds per square inch (PSI).
Wind Pressure Results
How do you convert wind speed to PSI?
A commonly used basic velocity-pressure relationship for wind speed in miles per hour is:
$$q = 0.00256V^2$$
This calculates wind pressure in pounds per square foot, or PSF. Because one square foot contains 144 square inches, convert PSF to PSI by dividing by 144.
$$PSI = \frac{PSF}{144}$$
Combining the two formulas:
$$PSI = \frac{0.00256V^2}{144}$$
What is the wind speed to PSI formula?
For wind speed in mph and basic velocity pressure:
$$PSI = 0.0000177778V^2$$
The result is the basic velocity pressure expressed in pounds per square inch.
Example: 100 mph wind to PSI
First calculate the pressure in PSF:
$$PSF = 0.00256 \times 100^2 = 25.6\ PSF$$
Then convert PSF to PSI:
$$PSI = \frac{25.6}{144} \approx 0.1778\ PSI$$
Why is wind pressure in PSI so small?
PSI is a much larger pressure unit than PSF because one square foot contains 144 square inches. Therefore, the numerical PSI value is much smaller than the corresponding PSF value.
$$1\ PSI = 144\ PSF$$
How does wind speed affect PSI?
Wind pressure increases with the square of wind speed. This means that doubling the wind speed produces four times the basic velocity pressure.
$$PSI \propto V^2$$
Wind Speed to PSI Chart
The following chart shows approximate basic wind pressure converted to PSI. Values use the standard relationship q = 0.00256V² with wind speed in mph and a pressure coefficient of 1.00.
| Wind Speed | Wind Speed (knots) | PSF | PSI |
|---|---|---|---|
| 20 mph | 17.38 kn | 1.02 PSF | 0.0071 PSI |
| 30 mph | 26.07 kn | 2.30 PSF | 0.0160 PSI |
| 40 mph | 34.75 kn | 4.10 PSF | 0.0284 PSI |
| 50 mph | 43.45 kn | 6.40 PSF | 0.0444 PSI |
| 60 mph | 52.15 kn | 9.22 PSF | 0.0640 PSI |
| 70 mph | 60.85 kn | 12.54 PSF | 0.0871 PSI |
| 80 mph | 69.49 kn | 16.38 PSF | 0.1138 PSI |
| 90 mph | 78.21 kn | 20.74 PSF | 0.1440 PSI |
| 100 mph | 86.98 kn | 25.60 PSF | 0.1778 PSI |
| 110 mph | 95.65 kn | 30.98 PSF | 0.2151 PSI |
| 120 mph | 104.24 kn | 36.86 PSF | 0.2559 PSI |
| 130 mph | 112.91 kn | 43.26 PSF | 0.3004 PSI |
| 140 mph | 121.67 kn | 50.18 PSF | 0.3485 PSI |
| 150 mph | 130.39 kn | 57.60 PSF | 0.4000 PSI |
| 160 mph | 139.04 kn | 65.54 PSF | 0.4551 PSI |
| 170 mph | 147.67 kn | 73.98 PSF | 0.5138 PSI |
| 180 mph | 156.27 kn | 82.94 PSF | 0.5759 PSI |
| 200 mph | 173.96 kn | 102.40 PSF | 0.7111 PSI |
How much PSI is 60 mph wind?
Using the basic velocity-pressure formula, 60 mph corresponds to approximately 9.22 PSF, which is about 0.064 PSI.
How much PSI is 80 mph wind?
An 80 mph wind corresponds to approximately 16.38 PSF, or about 0.114 PSI.
How much PSI is 100 mph wind?
A 100 mph wind corresponds to approximately 25.6 PSF, or 0.178 PSI.
How much PSI is 120 mph wind?
A 120 mph wind corresponds to approximately 36.86 PSF, or 0.256 PSI.
How much PSI is 150 mph wind?
A 150 mph wind corresponds to approximately 57.6 PSF, or 0.400 PSI.
How do you calculate PSI from PSF?
Divide PSF by 144:
$$PSI = \frac{PSF}{144}$$
Can wind pressure be used to calculate force?
Yes. Once pressure is known, a simplified force estimate can be calculated by multiplying pressure by the surface area.
$$Force = Pressure \times Area$$
$$Force_{lb} = PSF \times Area_{ft^2}$$
For example, 25.6 PSF acting over 100 square feet corresponds to approximately 2,560 pounds of distributed force before accounting for shape, pressure variation, attachment conditions, and other design factors.
Does the pressure coefficient change the wind speed?
No. The pressure coefficient changes the calculated pressure for a particular design condition. The actual wind speed remains the same.
$$Design\ Pressure = Basic\ Velocity\ Pressure \times C$$
Is wind speed to PSI the same as atmospheric pressure?
No. Wind-pressure calculations describe the dynamic pressure associated with moving air. Atmospheric pressure is the much larger ambient pressure of the atmosphere and is measured separately.
Is this a complete structural wind-load calculation?
No. This calculator provides a basic velocity-pressure conversion. Structural or building-code wind loads can require additional factors for exposure, height, gust response, surface shape, internal pressure, importance, and other site-specific conditions.
Wind speed to PSI FAQ
Using the basic velocity-pressure equation, 100 mph produces approximately 25.6 PSF, which is about 0.1778 PSI.
80 mph produces approximately 16.38 PSF, or 0.1138 PSI.
120 mph produces approximately 36.86 PSF, or 0.2559 PSI.
Convert the wind speed to mph, calculate PSF using q = 0.00256V², then divide the PSF result by 144 to obtain PSI.
Either unit can describe pressure, but PSF is commonly more convenient for distributed wind loads over building and structural surfaces. PSI is convenient when comparing pressure with other pressure values.