# Density Altitude Calculator

URL: https://speedycalculator.com/calculators/physics/density-altitude/
Last updated: 2026-10-30

> The density altitude calculator finds the pressure altitude, air density and density altitude at an airfield from its elevation, the altimeter setting, the temperature and the dew point.

## Inputs

- Field elevation (ft, m)
- Altimeter setting (QNH) (inHg, hPa)
- Outside air temperature (°C, °F, K)
- Dew point (°C, °F, K)

## Results

- Station pressure
- Vapour pressure
- Air density
- Pressure altitude
- Density altitude

## Formula

```
p_stn = (QNH^{0.190263} − 8.417286×10⁻⁵·elev)^{1/0.190263},  ρ = p_d/(R_dT) + p_v/(R_vT)
DA (km) = 44.3308 − 42.2665·ρ^{0.234969}
```

## Explanation

On hot, high and humid days aircraft perform as if the airfield were much higher: take-off runs lengthen and climb rates fall. Density altitude is that "as-if" altitude, and pilots check it before every hot-day departure.

### How to use the Density Altitude Calculator

- **Field elevation**
- **Altimeter setting (QNH)**
- **Outside air temperature**
- **Dew point**

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

### How it works

Enter the field elevation, the altimeter setting (QNH), the outside air temperature and the dew point.

### Inputs explained

FieldWhat to enterField elevationUnits: ft, mAltimeter setting (QNH)Units: inHg, hPaOutside air temperatureUnits: °C, °F, KDew pointUnits: °C, °F, K

### What each result means

- **Station pressure** = (([Altimeter setting (QNH)]÷100)^0.190263 - 8.417286e-5×[Field elevation])^(1÷0.190263)
- **Vapour pressure** = 6.112×exp(17.62×([Dew point])÷(243.12 + ([Dew point])))
- **Air density** = ([Station pressure] - [Vapour pressure])×100÷(287.058×([Outside air temperature] + 273.15)) + [Vapour pressure]×100÷(461.495×([Outside air temperature] + 273.15))
- **Pressure altitude** = (1 - ([Station pressure]÷1013.25)^0.190284)×145366.45×0.3048
- **Density altitude** = (44.3308 - 42.2665×[Air density]^0.234969)×1000

### Example values

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

Field elevation (ft)Density altitude (ft)7502,634.07061,1253,093.42961,5003,552.54031,8754,011.40262,2504,470.01633,0005,386.4981

## Worked example

Inputs — Field elevation: 1,500 ft; Altimeter setting (QNH): 30.12 inHg; Outside air temperature: 30 °C; Dew point: 15 °C.

Results — Station pressure = 965.9578 hPa; Vapour pressure = 17.01672 hPa; Air density = 1.10263 kg/m³; Pressure altitude = 1,316.145 ft; **Density altitude = 3,552.5403 ft**.

## Key terms

- **Density altitude**: Altitude in the standard atmosphere with the same air density.

## FAQ

**Why does density altitude matter?**
Aircraft and engines perform according to air density, not the field's elevation.

**What makes density altitude high?**
High elevation, high temperature, low pressure and humidity.

**What is pressure altitude?**
Altitude in the standard atmosphere with the same pressure.

**How much does it change per °C?**
Roughly 120 ft per °C above standard temperature.


## Sources

- [FAA – Pilot's Handbook of Aeronautical Knowledge](https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak)
- [NOAA / National Weather Service – Weather calculators](https://www.weather.gov/epz/wxcalc)