What is the density altitude?
Type the field elevation, the altimeter setting and the temperature, and the dew point if you have it. The density altitude calculator gives the density altitude, the pressure altitude, the standard temperature and a quick rule-of-thumb check.
- Density altitude
- 7,821 ft
The density altitude is 7,821 ft (pressure altitude 5,001 ft).
- Pressure altitude
- 5,001 ft
- Rule of thumb
- 7,960 ft
- ISA temperature (°C)
- 5.1
- Station pressure (hPa)
- 843
- Station pressure (inHg)
- 24.89
- Vapour pressure (hPa)
- 0
- Virtual temperature (°C)
- 30
- Density ratio (%)
- 79
Density altitude: 7,821 ft. The density altitude is 7,821 ft (pressure altitude 5,001 ft).
How to calculate
Density altitude calculator for pilots: density altitude from field elevation, altimeter setting, temperature and dew point, with the pressure altitude, the ISA temperature and the 118.8 ft per °C rule of thumb.
Example with the default inputs (Field elevation 5,000 ft, Altimeter setting 29.92 inHg, Outside air temperature 85.9999999999999 °F): The density altitude is 7,821 ft (pressure altitude 5,001 ft).
Method: PA = elevation + 145,366.45 × (1 − (A ÷ 1,013.25)^0.190284) ft; P = 1,013.25 × (1 − PA ÷ 145,366.45)^(1 ÷ 0.190284) hPa; e = 6.11 × 10^(7.5Td ÷ (237.7 + Td)) hPa; Tv = T ÷ (1 − (e ÷ P) × 0.378) K; DA = 145,442.16 × (1 − (17.326 × P_inHg ÷ (1.8 × Tv))^0.235) ft.
- The standard atmosphere: 1,013.25 hPa and 15 °C at sea level, cooling 1.9812 °C per 1,000 ft.
- Leave the dew point empty for dry air; humidity raises density altitude, often by a few hundred feet on a warm, humid day.
Worked examples
Each example is checked against the calculator on every build.
- Field elevation 0 ft, Altimeter setting 29.92 inHg, Outside air temperature 59 °F gives Pressure altitude 0 ft, ISA temperature (°C) 15, Density altitude 17 ft.Source: Wikipedia, Density altitude (DA = 145,442.16 × (1 − [17.326 × P ÷ T]^0.235), P in inHg, T in °R; DA ≈ PA + 118.8 × (OAT − ISA)), https://en.wikipedia.org/wiki/Density_altitude (retrieved 2026-10-05); Wikipedia, Pressure altitude (145,366.45 × [1 − (p ÷ 1,013.25)^0.190284] ft), https://en.wikipedia.org/wiki/Pressure_altitude (retrieved 2026-10-05)
- Field elevation 5,000 ft, Altimeter setting 29.92 inHg, Outside air temperature 86 °F gives Density altitude 7,821 ft, Rule of thumb 7,960 ft, Station pressure (hPa) 842.970887.Source: Wikipedia, Density altitude (DA = 145,442.16 × (1 − [17.326 × P ÷ T]^0.235), P in inHg, T in °R; DA ≈ PA + 118.8 × (OAT − ISA)), https://en.wikipedia.org/wiki/Density_altitude (retrieved 2026-10-05)
- Field elevation 5,000 ft, Altimeter setting 29.92 inHg, Outside air temperature 86 °F, Dew point 68 °F gives Vapour pressure (hPa) 23.340674, Density altitude 8,161 ft.Source: MetPod, Density Altitude (DA) Calculation, NOAA formulas e = 6.11 × 10^(7.5Td ÷ (237.7 + Td)) and Tv = T ÷ (1 − (e ÷ p)(1 − 0.622)), https://www.metpod.co.uk/calculators/density-alt/ (retrieved 2026-10-05); Wikipedia, Density altitude (DA = 145,442.16 × (1 − [17.326 × P ÷ T]^0.235), P in inHg, T in °R; DA ≈ PA + 118.8 × (OAT − ISA)), https://en.wikipedia.org/wiki/Density_altitude (retrieved 2026-10-05)
How it works
- Pressure altitude PA = elevation (ft) + 145,366.45 × (1 − (A ÷ 1,013.25)^0.190284), with A the altimeter setting in hPa. (An altimeter set to A reads the field elevation on the ground.)
- Station pressure P = 1,013.25 × (1 − PA ÷ 145,366.45)^(1 ÷ 0.190284) hPa, and P in inHg = P × 100 ÷ 3,386.388640341 (1 inHg = 13.5951 × 9.80665 × 25.4 Pa).
- Vapour pressure e = 6.11 × 10^(7.5 × Td ÷ (237.7 + Td)) hPa, with Td the dew point in °C; e = 0 when the dew point is left empty.
- Virtual temperature Tv = T ÷ (1 − (e ÷ P) × (1 − 0.622)), with T in kelvins.
- Density altitude DA = 145,442.16 × (1 − (17.326 × P_inHg ÷ (1.8 × Tv))^0.235) feet; 1.8 × Tv is Tv in °R.
Also shown:
- ISA temperature = 15 − 1.9812 × PA ÷ 1,000 °C.
- Rule of thumb = PA + 118.8 × (T in °C − ISA temperature), ignoring humidity.
- Density ratio = 17.326 × P_inHg ÷ (1.8 × Tv), as a percentage.
Rules
- Elevation from −1,500 ft to 20,000 ft; altimeter setting from 900 to 1,100 hPa (26.58 to 32.48 inHg); temperature and dew point from −60 °C to 60 °C.
- A dew point above the air temperature has no answer.
Output format
Density altitude, pressure altitude and the rule of thumb in feet (US) or metres (Metric) to whole units; temperatures in °C to 1 decimal; station pressure in hPa to 1 decimal and inHg to 2 decimals; vapour pressure in hPa to 2 decimals; the density ratio in percent to 1 decimal. All arithmetic is in floats (powers).
Worked examples by hand
Standard day at sea level. A = 1,013.25 hPa, 15 °C, dry: PA = 0, P = 29.9213 inHg, T = 518.67 °R, 17.326 × 29.9213 ÷ 518.67 = 0.99951, DA = 145,442.16 × (1 − 0.99951^0.235) = 16.76 ft. It is not exactly 0 because 17.326 is a rounded constant.
A hot day. 5,000 ft field, 29.92 inHg (1,013.21 hPa), 30 °C, dry: PA = 5,001.16 ft, P = 842.97 hPa = 24.8929 inHg, T = 545.67 °R, ratio 0.790395, DA = 7,821.5 ft. ISA = 5.09 °C, so the rule of thumb gives 5,001.16 + 118.8 × 24.91 = 7,960.3 ft.
The same day, humid. Dew point 20 °C: e = 6.11 × 10^(150 ÷ 257.7) = 23.341 hPa; Tv = 303.15 ÷ (1 − 23.341 ÷ 842.97 × 0.378) = 306.356 K; ratio 0.782122; DA = 8,161.3 ft, 340 ft higher than dry air.
Other questions people ask
How do you calculate density altitude?
Find the pressure altitude and the station pressure, then the density altitude from the air density: DA = 145,442.16 × (1 − (17.326 × P ÷ T)^0.235) ft, with P the station pressure in inHg and T the (virtual) temperature in °R. A 5,000 ft field at 29.92 inHg and 30 °C in dry air gives about 7,821 ft.
What is the rule of thumb for density altitude?
DA ≈ pressure altitude + 118.8 ft for each °C the air is warmer than the standard temperature. Many pilot guides round this to 120 ft per °C. It ignores humidity.
Why does density altitude matter?
Engines make less power, propellers and wings get less lift, and the aircraft needs a longer takeoff roll and climbs more slowly when the air is thin. Performance charts use density altitude for this.
Does humidity raise density altitude?
Yes. Water vapour is lighter than dry air, so humid air is less dense. On a 30 °C day at a 5,000 ft field, a 20 °C dew point raises the density altitude by about 340 ft.
What is the standard temperature at altitude?
The standard atmosphere is 15 °C at sea level and cools about 1.98 °C per 1,000 ft (6.5 °C per km), so it is about 5 °C at 5,000 ft.
Is density altitude the same as pressure altitude?
Only on a standard day. Pressure altitude corrects for pressure alone; density altitude also corrects for temperature and humidity.