Atm Conversion
Convert between atmospheres (atm), pascals (Pa), kilopascals (kPa), megapascals (MPa), bar, psi, mmHg, and torr with this free online pressure converter. Comparison chart shows your value across all pressure units at once.
About This Calculator
This free online pressure conversion calculator lets you convert any value between eight common pressure units: atmospheres (atm), pascals (Pa), kilopascals (kPa), megapascals (MPa), bar, pounds per square inch (psi), millimeters of mercury (mmHg), and torr. Select the unit you are converting from and the unit you want to convert to, enter your value, and get an instant result with a full comparison chart showing the equivalent value across every supported pressure unit.
Whether you are a student studying gas laws in chemistry, an engineer working with hydraulic systems, a diver planning a decompression schedule, or a meteorologist comparing atmospheric pressure readings from different instruments, this converter handles it all with precision up to six decimal places.
Frequently Asked Questions
How does the Atm Conversion calculator work?
Enter a numeric value, select the pressure unit you are converting from (e.g. atm, bar, psi), and choose the target unit. The calculator instantly converts using standard conversion factors based on the pascal base unit and displays a comparison chart of all pressure units.
Is this pressure conversion tool free?
Yes, all calculators on Calculy are completely free to use with no registration or hidden charges.
What pressure units can I convert between?
You can convert between all common pressure units: atmosphere (atm), pascal (Pa), kilopascal (kPa), megapascal (MPa), bar, pounds per square inch (psi), millimeter of mercury (mmHg), and torr.
How do you convert 1 atm to pascals?
1 standard atmosphere (atm) equals 101,325 pascals (Pa). This is the internationally defined conversion factor used in scientific and engineering calculations worldwide.
What is 1 bar in atm?
1 bar equals approximately 0.9869 atm. Conversely, 1 atm equals about 1.01325 bar. This small difference matters in precision applications like tire pressure, meteorology, and industrial process control.
How do I convert psi to atm?
To convert psi to atm, multiply the psi value by 0.068046. For example, 14.7 psi (standard atmospheric pressure at sea level) equals approximately 1 atm. This converter does the math instantly for any value.
What is the relationship between mmHg and atm?
760 mmHg equals exactly 1 atm. This relationship comes from the original definition of the atmosphere based on mercury barometers. The torr is defined identically to mmHg, so 760 torr also equals 1 atm.
Why would I need an atmospheric pressure converter?
Pressure conversion is essential in meteorology, aviation, scuba diving, HVAC engineering, automotive tire pressure, medical devices (ventilators and blood pressure monitors), chemistry lab work, and industrial process control where different instruments use different pressure units.