# Crosswind Calculator

URL: https://speedycalculator.com/calculators/everyday-life/crosswind/
Last updated: 2026-10-25

> The crosswind calculator splits the wind into crosswind and headwind (or tailwind) components for a runway or direction of travel, as pilots do before take-off and landing.

## Inputs

- Runway number (heading ÷ 10)
- Wind direction (from) (°)
- Wind speed (knots, mph, km/h, m/s)

## Results

- Wind angle to runway
- Crosswind component
- Headwind (+) / tailwind (−)
- Crosswind from the

## Formula

```
Angle α = wind direction − runway heading (runway number × 10)
Crosswind = wind speed × sin α
Headwind = wind speed × cos α (negative = tailwind)
```

## Explanation

Runways are numbered by their magnetic heading in tens of degrees – runway 27 points 270°. Wind is reported by the direction it blows from. Aircraft have a maximum demonstrated crosswind, and tailwinds lengthen take-off and landing distances, so pilots choose the runway that gives the most headwind.

### How to use the Crosswind Calculator

- **Runway number (heading ÷ 10)**
- **Wind direction (from)**
- **Wind speed**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter the runway number (or your heading ÷ 10), the wind direction it is blowing from and the wind speed.

### Tips

- Use your own measured figures – fuel economy, speed and prices vary a lot with driving style, traffic, load and season.
- Pick the unit in each field's menu (miles or kilometres, mpg or L/100 km); the calculator converts everything for you.
- Fill up to the brim twice and divide the distance by the fuel added to measure real fuel economy.
- For vehicle modifications, treat results as a starting point and confirm with the parts maker or a professional mechanic.

### Common mistakes to avoid

- Mixing US and imperial (UK) gallons – a UK gallon is about 20% bigger.
- Using the advertised fuel economy instead of real-world figures.
- Forgetting tolls, parking and wear and tear when comparing driving with public transport.

### Inputs explained

FieldWhat to enterRunway number (heading ÷ 10)A numberWind direction (from)Units: °Wind speedUnits: knots, mph, km/h, m/s

### What each result means

- **Wind angle to runway** = mod([Wind direction (from)] - [Runway number (heading ÷ 10)]×10 + 180, 360) - 180
- **Crosswind component** = abs([Wind speed]×sin(rad([Wind angle to runway])))
- **Headwind (+) / tailwind (−)** = [Wind speed]×cos(rad([Wind angle to runway]))

### Example values

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

Runway number (heading ÷ 10)Crosswind component (knots)13.55.220.2519.8271033.7512.2

## Worked example

Inputs — Runway number (heading ÷ 10): 27; Wind direction (from): 300 °; Wind speed: 20 knots.

Results — Wind angle to runway = 30 °; **Crosswind component = 10 knots**; Headwind (+) / tailwind (−) = 17.3 knots; Crosswind from the = right.

## FAQ

**How do I estimate crosswind quickly?**
Pilots use the clock method: 15° off = ¼ of the wind, 30° = ½, 45° = ¾, 60° or more = all of it.

**What is a maximum demonstrated crosswind?**
The strongest crosswind tested during certification – about 12–15 kt for many light aircraft. It is not a legal limit, but a useful guide.

**Why is tailwind bad for take-off?**
It increases ground speed at lift-off, lengthening the take-off run considerably.

**What formula does the Crosswind Calculator use?**
Angle α = wind direction − runway heading (runway number × 10).


## Sources

- [FAA – Airplane Flying Handbook, crosswind operations](https://www.faa.gov/)