Estimate pressure at altitude or elevation. Enter altitude, sea-level pressure, and reference temperature to calculate air pressure in PSI, kPa, hPa, pascals, bar, atmospheres, mmHg, inHg, and percent of sea-level pressure.
Altitude:
Enter elevation above or below sea level. Higher altitude has lower pressure because there is less air above the location.
Sea-level pressure:
Use 1013.25 hPa for standard atmosphere, or enter a local sea-level pressure value if known.
Temperature mode:
Standard mode uses standard atmosphere temperature. Temperature adjusted mode uses your reference temperature for a rough correction.
An altitude pressure calculator is useful for hiking, aviation examples, mountain conditions, weather, science lessons, pressure conversions, HVAC examples, and estimating how much pressure changes with elevation.
This calculator estimates atmospheric pressure. Actual local pressure changes with weather, temperature, humidity, storms, and measurement conditions.
A common pressure at altitude estimate is:
P = P₀ × (1 - Lh / T₀)5.255
Atmospheric pressure decreases as altitude increases because there is less air above that elevation pressing downward.
Standard sea-level pressure is about 1013.25 hPa, 101.325 kPa, 14.696 PSI, 29.92 inHg, or 1 atmosphere.
Under standard atmosphere conditions, pressure at 5,280 feet is about 12.2 PSI, or roughly 83% of sea-level pressure.
Altitude pressure is the estimated atmospheric pressure at a given elevation. Barometric pressure is atmospheric pressure measured by a barometer and is often adjusted to sea level for weather reports.