Converting Pascals to Atmospheres Example

Worked Pa to atm Pressure Unit Conversion Problem

Pascals and atmospheres are units of pressure.
Pascals and atmospheres are units of pressure. Tetra Images - Jessica Peterson, Getty Images
by Anne Marie Helmenstine, Ph.D.
Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
Updated May 07, 2019

This example problem demonstrates how to convert the pressure units pascals (Pa) to atmospheres (atm). Pascal is a SI pressure unit that refers to newtons per square meter. Atmosphere originally was a unit related to the air pressure at sea level. It was later defined as 1.01325 x 105 Pa.

Pa to Atm Problem

The air pressure outside a cruising jet liner is approximately 2.3 x 104 Pa. What is this pressure in atmospheres?
Solution:
1 atm = 1.01325 x 105 Pa
Set up the conversion so the desired unit will be cancelled out. In this case, we want Pa to be the remaining unit.
pressure in atm = (pressure in Pa) x (1 atm/1.01325 x 105 Pa)
pressure in atm = (2.3 x 104/1.01325 x 105) Pa
pressure in atm = 0.203 atm
Answer:
The air pressure at cruising altitude is 0.203 atm.

Check Your Work

One quick check you should do to make sure your answer is reasonable is to compare the answer in atmospheres to the value in pascals. The atm value should be about 10,000 times smaller than the number in pascals.