Wind Pressure Calculator

How it is calculated

Enter the wind speed v in metres per second. The tool computes the dynamic pressure q = 0.613 × v² in pascals (Pa), then converts it to pounds per square foot with psf = Pa × 0.0208854. The constant 0.613 is half the standard air density at sea level (1.225 kg/m³) and assumes that density; thinner air at altitude or hot weather gives somewhat lower pressure.

Because speed is squared, the pressure grows quickly: doubling the speed quadruples q. Only a negative speed gives no result; zero returns 0. The figure is the free-stream pressure only. It does not include shape, height, exposure or gust factors that a design code applies on top, so it is not a design load by itself. Speeds in km/h, mph or knots must be converted to m/s first.

Common mistakes

• Entering km/h or mph as if it were m/s. 90 km/h is 25 m/s; typing 90 gives a pressure about thirteen times too high.
• Expecting pressure to scale in a straight line with speed. Because of the square, 50 m/s gives four times the pressure of 25 m/s, not twice.
• Using the result as the final design load on a sign or panel. It is the base pressure only, and codes multiply it by shape, exposure and gust coefficients.
• Multiplying by a surface area in square metres and reading the answer as kilograms. Pa times m² gives newtons, not kilograms.
• Applying the sea-level constant at high altitude. The 0.613 factor assumes standard air density, so the pressure is overestimated where the air is thinner.