Gas Pressure Conversion Calculator
Convert pressure between atmospheres, kPa, psi, mmHg (torr), and bar — the units every gas law problem mixes.
Converted values
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kPa —
PSI —
mmHg —
Bar —
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How it works
1 atm = 101.325 kPa = 14.696 psi = 760 mmHg = 1.01325 barFrequently Asked Questions
How do I convert atm to psi?
Multiply by 14.696: 2 atm equals about 29.39 psi. These conversion factors are exact by definition, so results are precise regardless of the value being converted.
What is the difference between mmHg and torr?
They're essentially identical (1 torr = 1 mmHg to a very high precision), both representing the pressure exerted by a column of mercury — a legacy unit from early barometers still common in medicine and chemistry.
Why do gas law problems use different units?
Different fields have different conventions: chemistry often uses atm, engineering uses psi or bar, and meteorology uses hPa (equivalent to mbar). Converting cleanly between them is essential before plugging into PV=nRT.