How this calculator works
Dynamic pressure is one half of density times speed squared. Multiply by a drag coefficient and its matching projected area to estimate force. The input angle is between the surface plane and the wind, so a face-on surface is 90 degrees. Projection changes the area only; the real drag coefficient may also change with inclination. This steady uniform-flow estimate omits gusts, exposure, shielding, internal pressure and structural response. It is not a building-code design load.
Formula
q = rho V^2/2; A_projected = A sin(alpha); F = q Cd A_projected. Use a coefficient defined with the same reference area.
Worked example
At density 1.225 kg/m3 and 20 m/s, dynamic pressure is 245 Pa. With Cd = 1, a face-on 10 m2 surface has estimated force 2450 N.
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Frequently asked questions
Which angle is face-on?
90 degrees. Zero degrees means the ideal surface plane is parallel to the wind.
What coefficient should I use?
Use a measured or published coefficient for the shape, flow regime and reference-area convention.
Is this sufficient for a roof or sign design?
No. Applicable structural standards require more loading factors and load combinations.