Wind Speed to PSF Calculator
Convert wind speed to wind pressure in pounds per square foot (PSF), or convert wind pressure back to the equivalent wind speed. Use the standard velocity-pressure relationship for a quick wind-load estimate.
Wind Pressure Results
How is wind speed converted to PSF?
A commonly used velocity-pressure relationship for wind speed expressed in miles per hour is:
$$q = 0.00256V^2$$
- q: velocity pressure in pounds per square foot (PSF).
- V: wind speed in miles per hour (mph).
This produces the basic velocity pressure before applying any project-specific pressure coefficient.
How do you convert PSF to wind speed?
Rearranging the same relationship gives:
$$V = \sqrt{\frac{q}{0.00256}}$$
This provides the equivalent wind speed in mph when the entered pressure is the base velocity pressure.
Example: 100 mph wind to PSF
For a wind speed of 100 mph:
$$q = 0.00256 \times 100^2$$
$$q = 25.6\ PSF$$
Therefore, a 100 mph wind corresponds to approximately 25.6 PSF of basic velocity pressure using this relationship.
Example: 30 PSF to wind speed
To determine the equivalent wind speed for 30 PSF:
$$V = \sqrt{\frac{30}{0.00256}}$$
$$V \approx 108.25\ mph$$
Wind speed to PSF table
| Wind Speed | Base Pressure | Approx. PSF |
|---|---|---|
| 50 mph | 0.00256 × 50² | 6.40 PSF |
| 60 mph | 0.00256 × 60² | 9.22 PSF |
| 70 mph | 0.00256 × 70² | 12.54 PSF |
| 80 mph | 0.00256 × 80² | 16.38 PSF |
| 90 mph | 0.00256 × 90² | 20.74 PSF |
| 100 mph | 0.00256 × 100² | 25.60 PSF |
| 110 mph | 0.00256 × 110² | 30.98 PSF |
| 120 mph | 0.00256 × 120² | 36.86 PSF |
Does wind pressure increase linearly with wind speed?
No. The basic velocity pressure varies with the square of wind speed. This means that a relatively modest increase in wind speed can produce a substantially larger pressure.
$$q \propto V^2$$
For example, doubling the wind speed results in four times the basic velocity pressure.
What is the difference between wind speed and wind pressure?
Wind speed describes how fast the air is moving. Wind pressure describes the dynamic pressure associated with that moving air. Pressure is useful when estimating forces acting on structures, panels, signs, roofs, covers, and other surfaces.
What is PSF?
PSF means pounds per square foot. It is a unit of pressure or distributed load commonly used in building, structural, marine, and engineering applications.
$$1\ PSF = 1\ pound\ of\ force\ per\ square\ foot$$
What is the wind pressure formula in mph?
For the common basic velocity-pressure approximation:
$$q = 0.00256V^2$$
The coefficient 0.00256 incorporates the density conversion used for this particular unit system and approximation.
Why is a pressure coefficient sometimes needed?
Actual design wind pressure on a surface is not always equal to the basic velocity pressure. Surface shape, orientation, exposure, internal pressure, height, gust effects, and other design conditions can influence the final design pressure.
This calculator therefore provides an optional coefficient that can multiply the base velocity pressure.
$$Design\ Pressure = q \times C$$
Here C represents the pressure coefficient entered by the user.
Can this calculator be used for boat covers?
It can provide a basic wind-pressure estimate for preliminary calculations involving boat covers, canopies, canvas, panels, and similar surfaces. The actual force on a boat cover depends on its shape, orientation, tension, attachment points, exposure, and aerodynamic behavior.
How do you calculate wind force from PSF?
Once a design pressure in PSF is known, the approximate force on a flat area can be calculated by multiplying pressure by area.
$$Force = Pressure \times Area$$
$$Force_{lb} = PSF \times Area_{ft^2}$$
For example, 25.6 PSF acting over 100 square feet corresponds to a simplified total distributed force of approximately 2,560 pounds. Actual structural wind loads can be more complicated because pressure is not necessarily uniform across an entire surface.
Is wind speed to PSF a structural design calculation?
The basic conversion is useful for estimating velocity pressure, but it should not automatically be treated as a complete structural design wind-load calculation.
Building and structural design may require code-specific wind speeds, exposure categories, importance factors, gust effects, pressure coefficients, internal pressure, height adjustments, and other requirements.
Wind speed to PSF FAQ
Using q = 0.00256V², a 100 mph wind produces a basic velocity pressure of approximately 25.6 PSF.
Using the same basic relationship, 20 PSF corresponds to approximately 88.4 mph.
30 PSF corresponds to approximately 108.3 mph using the basic velocity-pressure formula.
A 60 mph wind corresponds to approximately 9.22 PSF of basic velocity pressure using q = 0.00256V².
Divide PSF by 0.00256 and take the square root: V = √(PSF ÷ 0.00256).
No. Using the basic velocity-pressure relationship, 100 mph corresponds to approximately 25.6 PSF before any additional design coefficients are applied.