Enter your pressure value in Value to Convert, pick your From and To units, and the Pressure Conversion Calculator gives you the converted value along with the conversion formula so you can see exactly how the math works.
Converted Value
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Conversion Formula
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One atmosphere (atm) equals 1.01325 bar. Atmosphere is based on Earth's average atmospheric pressure at sea level, while bar is a metric unit where 1 bar equals 100,000 Pascals.
To convert PSI to bar, multiply the PSI value by 0.0689476. For example, 14.7 PSI × 0.0689476 = 1.01325 bar (which equals 1 atmosphere).
mmHg (millimeters of mercury) and Torr are essentially the same unit. 1 Torr = 1 mmHg = 133.322 Pascals. The Torr is named after physicist Evangelista Torricelli.
Different industries use different pressure units based on convenience and historical reasons. For example, meteorology uses mmHg or mbar, engineering uses PSI or bar, and physics uses Pascals.
Standard atmospheric pressure is 1 atmosphere (atm) = 101,325 Pascals = 1.01325 bar = 14.696 PSI = 760 mmHg = 760 Torr. This is the average pressure at sea level.
This calculator uses precise conversion factors and provides results accurate to 6 decimal places. The conversion factors are based on internationally recognized standards.