Atmospheres (atm) Pressure Converter
Convert pressure in standard atmospheres (atm) to other common pressure units — pascals, kilopascals, bar, pounds per square inch and millimetres of mercury. One standard atmosphere equals 101,325 Pa. Enter a value in atm and choose the unit you want to convert it to.
Formula
1 atm = 101,325 Pa = 101.325 kPa = 1.01325 bar = 14.6959 psi = 760 mmHg
- Standard atmosphere (atm) is a fixed reference pressure equal to exactly 101,325 pascals.
- Each target unit uses a constant factor: multiply the atm value by 101.325 for kPa, 1.01325 for bar, 14.6959 for psi, or 760 for mmHg.
- The result is also shown in pascals for a consistent SI reference regardless of the unit you choose.
- To convert the other way, divide the value in the chosen unit by the same factor to get atmospheres.
Example: 1 atm to kPa
Inputs
- Pressure (atm): 1
- Convert To: kPa
One standard atmosphere equals 101.325 kPa (and 101,325 Pa), so entering 1 atm with kPa selected returns 101.325.
Frequently asked questions
What is one atmosphere in pascals?
Exactly 101,325 Pa, which is also 101.325 kPa. This is the standard atmosphere used as a reference pressure.
How many psi is one atmosphere?
About 14.6959 psi (pounds per square inch). Multiply any atm value by 14.6959 to get psi.
How do I convert atm to bar?
Multiply by 1.01325. So 1 atm = 1.01325 bar, and 2 atm = 2.0265 bar.
What is 1 atm in mmHg?
Exactly 760 mmHg (millimetres of mercury), the classic value for standard atmospheric pressure at sea level.
How do I convert back to atmospheres?
Divide your pressure by the unit's factor — for example kPa ÷ 101.325, or psi ÷ 14.6959 — to recover the value in atm.