Atmosphere Pascal Converter
Convert standard atmosphere (atm) and pascal (Pa) from the same pressure value. Enter a value to update the result window plus kPa and bar summary cards.
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Read standard atmosphere and pascal as the same pressure
This converter changes a pressure value between standard atmosphere (atm) and pascal (Pa). Pascal is the SI pressure unit used in science and engineering, while atm is often used to describe pressure relative to a standard sea-level atmosphere.
Use the left window for the value you have and the right window for the converted value. The conversion uses 1 atm = 101,325 Pa. The summary cards keep atm, Pa, kPa, and bar visible so large pressure numbers are easier to compare.
Use it in screen order
- Leave the input in atm mode to convert atm to Pa. The default 1 atm becomes 101,325 Pa.
- Use Switch direction when your source value is in Pa and you need atm.
- kPa is Pa divided by 1000, so 101,325 Pa is 101.325 kPa.
- Copy both the original and converted units when pressure conditions need to be documented.
Units and basis
- Pa means pascal, the SI unit of pressure.
- atm means standard atmosphere. NIST lists 1 atm = 101,325 Pa.
- 1 atm equals 101.325 kPa, a convenient scale for atmospheric pressure.
- bar equals 100,000 Pa and is a common non-SI pressure unit.
Example conversions
The conversion is direct once the standard atmosphere value is fixed.
Cautions
- atm is a standard pressure unit; real atmospheric pressure changes with altitude and weather.
- Absolute pressure and gauge pressure use different reference points. Unit conversion alone does not change that reference.
- Pa values can be large, so kPa or bar may be easier to read in reports.
- This page converts units only. Equipment safety still depends on rated pressure and operating conditions.
Input values and conversion direction
Enter zero or a positive value, using a decimal point as in 0.5. Negative values are not accepted; use the swap button to switch between atm→Pa and Pa→atm.
Conversion factor and measurement precision
The relationship 1 atm = 101,325 Pa is exact, but converting units does not make the original measurement more precise. When recording a result, consider the precision of your input and include the unit Pa or atm.
FAQ
How many pascals are in one atmosphere?
1 standard atmosphere is 101,325 Pa, or 101.325 kPa.
What is the difference between Pa and kPa?
1 kPa is 1000 Pa. kPa is often easier to read for larger pressure values.
Is atm the same as real air pressure?
atm is a standard atmosphere unit. Actual air pressure varies with altitude and weather.
Is bar also a pressure unit?
Yes. 1 bar equals 100,000 Pa, so 1 atm is about 1.01325 bar.
Can I convert absolute and gauge pressure?
The units can be converted, but absolute and gauge pressure use different zero references. Keep abs, absolute, gauge, or g labels with the value.
What is the formula for converting atm to Pa?
Multiply the value in atm by 101,325 to get Pa. For example, 0.5 atm × 101,325 = 50,662.5 Pa.
How do I convert Pa to atm?
Divide the value in Pa by 101,325. For example, 202,650 Pa ÷ 101,325 = 2 atm.
Why can’t I enter a negative pressure value?
This tool accepts only values of 0 or more. Use a tool that supports negative values when working with negative gauge pressure. Changing units does not convert between absolute and gauge pressure.
References used
The standard atmosphere relationship follows the NIST Guide to the SI Appendix B conversion factors for standard atmosphere to pascal.