Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Density altitude
11,786
Pressure altitude
5,650
Standard (ISA) temp at this altitude
38.9
Degrees above/below ISA standard
51.1
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How to use this
- 1Enter field elevation (ft).
- 2Enter station (altimeter) pressure (inHg).
- 3Enter outside air temperature (°F).
- 4Read your density altitude on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
Pressure altitude and density altitude are critical for pilots, high-altitude athletes, and anyone trying to understand why the same physical elevation performs differently on a hot day versus a cold one. Pressure altitude adjusts your field elevation for non-standard barometric pressure relative to the standard atmosphere (29.92 inHg at sea level), while density altitude further adjusts for temperature — hot air is less dense, so a hot day at a given elevation behaves like a much higher, thinner-air elevation for aircraft performance, engine combustion, and human oxygen availability. This is exactly why aircraft need longer runways on hot summer afternoons at high-elevation airports, and why marathon times at altitude get worse on unusually warm race days.
Worked example
Using the values the calculator loads with:
Inputs
- Field elevation: 5430 ft
- Station (altimeter) pressure: 29.7 inHg
- Outside air temperature: 90 °F
Results
- Density altitude: 11,786
- Pressure altitude: 5,650
- Standard (ISA) temp at this altitude: 38.9
- Degrees above/below ISA standard: 51.1
What each field means
Inputs
- Field elevation (ft)
- The field elevation used in the calculation, measured in ft. Starts at 5430 ft so you have a working example on load. Accepted range: -300–15000 ft.
- Station (altimeter) pressure (inHg)
- The station (altimeter) pressure used in the calculation, measured in inHg. Starts at 29.7 inHg so you have a working example on load. Accepted range: 27–31.5 inHg.
- Outside air temperature (°F)
- The outside air temperature used in the calculation, measured in °F. Starts at 90 °F so you have a working example on load. Accepted range: -30–120 °F.
Results
- Density altitude
- Returned as a whole number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Pressure altitude
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Standard (ISA) temp at this altitude
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Degrees above/below ISA standard
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why do pilots care about density altitude so much?
Engine power, propeller efficiency, and wing lift all depend on actual air density, not indicated elevation. High density altitude (hot day, high elevation, low pressure) means longer takeoff rolls, reduced climb rate, and lower service ceilings — a major factor in high-elevation airport accidents historically.
How does this affect human performance at altitude?
Density altitude correlates with available oxygen partial pressure, so a hot day at a mile-high stadium can present the body with effectively higher-altitude conditions than the field elevation suggests, which is part of why altitude training camps and events monitor weather conditions closely, not just fixed elevation.
Where do I get current station pressure?
Local ATIS/AWOS broadcasts at airports report current altimeter setting directly; for non-aviation use, most weather apps report 'pressure' either as station pressure or sea-level-adjusted pressure, so make sure you're using the actual local station reading, not the sea-level-corrected value.
Why is the density altitude formula only approximate?
The full calculation involves the ideal gas law applied to actual vs. standard atmosphere air density, plus humidity effects (humid air is actually less dense than dry air at the same temperature and pressure). This simplified version captures the dominant temperature effect, accurate to within a few hundred feet for most conditions.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Barometric Pressure Altitude Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/barometric-pressure-altitude
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/barometric-pressure-altitude" target="_blank" rel="noopener">Barometric Pressure Altitude Calculator — RevenueLab</a> (2026).</p>
Source: [Barometric Pressure Altitude Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/barometric-pressure-altitude) (2026).