# Wind Load Calculator

URL: https://speedycalculator.com/calculators/physics/wind-load/
Last updated: 2026-10-30

> The wind load calculator estimates the force of wind on a surface – a sign, wall, solar panel or fence – from the wind speed, air density, area, drag (force) coefficient and the angle of the wind.

## Inputs

- Wind speed (km/h, m/s, mph, knots, ft/s)
- Air density (kg/m³, g/cm³, g/mL, lb/ft³, lb/in³)
- Surface area (m², cm², mm², km², in², ft²)
- Force (drag) coefficient
- Wind angle to the surface (°, rad, arcmin, arcsec, mrad)

## Results

- Dynamic (velocity) pressure
- Wind load
- Equivalent weight

## Formula

```
q = ½·ρ·v²,  F = q·A·C_d·sin α
```

## Explanation

Wind pushes on everything in its way, and the force grows with the square of the wind speed: a 100 km/h gust pushes four times harder than a 50 km/h one. Engineers use this to size signs, roofs, solar mounts and fences.

### How to use the Wind Load Calculator

- **Wind speed**
- **Air density**
- **Surface area**
- **Force (drag) coefficient**
- **Wind angle to the surface**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Enter the wind speed, area, force coefficient (2.0 is typical for flat signs and plates) and the angle between the wind and the surface (90° = face on).

### Inputs explained

FieldWhat to enterWind speedUnits: km/h, m/s, mph, knots, ft/sAir densityUnits: kg/m³, g/cm³, g/mL, lb/ft³, lb/in³Surface areaUnits: m², cm², mm², km², in², ft²Force (drag) coefficientA numberWind angle to the surfaceUnits: °, rad, arcmin, arcsec, mrad

### What each result means

- **Dynamic (velocity) pressure** = 0.5×[Air density]×[Wind speed]^2
- **Wind load** = 0.5×[Air density]×[Wind speed]^2×[Surface area]×[Force (drag) coefficient]×sin(rad([Wind angle to the surface]))
- **Equivalent weight** = [Wind load]÷9.80665

### Example values

How the main result changes when **Wind speed** changes and everything else stays at the example values above:

Wind speed (km/h)Wind load (N)50472.608751,063.36811001,890.43211252,953.80021504,253.47222007,561.7284

## Worked example

Inputs — Wind speed: 100 km/h; Air density: 1.225 kg/m³; Surface area: 2 m²; Force (drag) coefficient: 2; Wind angle to the surface: 90 °.

Results — Dynamic (velocity) pressure = 472.60802 Pa; **Wind load = 1,890.4321 N**; Equivalent weight = 192.7704 kgf.

## Key terms

- **Dynamic pressure**: Kinetic energy per unit volume of moving air.

## FAQ

**Why does wind load grow so fast with speed?**
It is proportional to v².

**What force coefficient should I use?**
About 1.2 for long cylinders, 2.0 for flat signs, more for some open frames.

**Do building codes use this?**
Codes add gust, exposure and importance factors – use them for real designs.

**What is velocity pressure?**
The dynamic pressure of the wind, ½ρv².


## Sources

- [The Engineering ToolBox](https://www.engineeringtoolbox.com/)
- [ASCE 7 – Minimum design loads (overview)](https://www.asce.org/publications-and-news/asce-7)