Estimate atmospheric pressure at a given elevation or altitude. This calculator uses a standard atmosphere approximation and converts pressure into PSI, kPa, pascals, hPa, millibars, bar, atmospheres, mmHg, and inHg.
Altitude:
Enter the elevation above or below sea level. Higher altitude means less air above you and lower pressure.
Sea level pressure:
Use standard pressure of 1013.25 hPa, or enter a local sea-level pressure value when available.
Temperature adjustment:
Use standard atmosphere for general estimates, or temperature adjusted mode for a rough correction based on reference temperature.
An atmospheric pressure calculator is useful for weather, hiking, aviation examples, altitude estimates, science lessons, HVAC examples, pressure conversions, and understanding air pressure changes with elevation.
This calculator gives an estimate. Actual atmospheric pressure changes with weather, temperature, humidity, and local conditions.
A common standard atmosphere estimate is:
P = P₀ × (1 - Lh / T₀)5.255
Standard atmospheric pressure at sea level is about 1013.25 hPa, 101.325 kPa, 14.696 PSI, or 1 atmosphere.
Yes. Atmospheric pressure decreases as altitude increases because there is less air above that elevation.
They are closely related. Barometric pressure is atmospheric pressure measured by a barometer, often reported as sea-level adjusted pressure.
High-pressure and low-pressure systems change the weight and movement of air above a location, which changes measured atmospheric pressure.