Wind Load Calculator
Dynamic wind pressure and the force on a flat surface, with the overturning moment about its base.
Results
What this tool does
Pressure goes with the square of the wind speed, so a storm at 30 m/s pushes four times as hard as a stiff breeze at 15 — which is why structures survive years of wind and then fail in a single gust. Air density is about 1.25 kg/m³ at sea level, less when it is hot and less again at altitude.
Formula
q = ½ ρ v² ; F = q × Cf × A
Variables
| Symbol | Meaning | Unit |
|---|---|---|
vw | Wind speed | m/s |
ro | Air density | kg/m³ |
cf | Force coefficient | — |
aa | Area | m² |
hh | Height | m |
QQ | Dynamic pressure | Pa |
FF | Force | kN |
KH | Wind speed | km/h |
MO | Overturning moment | kN·m |
PA | Pressure | Pa |
Worked example
- Wind speed30 m/s
- Air density1.25 kg/m³
- Force coefficient1.2
- Area20 m²
- Height3 m
- Dynamic pressure562.500 Pa
- Force13.5000 kN
- Wind speed108.00 km/h
- Overturning moment20.2500 kN·m
- Pressure675.000 Pa
Limitations
- For work that must comply with a standard or be signed off, check the result against the applicable code and have it reviewed by a qualified engineer.
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- The formula assumes ideal conditions: no friction losses, no air resistance and no efficiency losses unless you enter them.
Frequently asked questions
Can I design a fence or a sign with this?
Not on its own. This gives the basic dynamic pressure, which is genuine physics, but a design wind load also needs the site's basic wind speed from the national map, corrections for terrain roughness, height above ground, topography and gusting, and the right pressure coefficients for the shape including suction on the leeward face. Those all come from the applicable code — Eurocode 1 part 1-4 in Europe. Use this to understand the magnitudes and to sanity-check a result.