Science, Tech, Math › Science Converting Pounds Per Square Inch or PSI to Millibars Worked Pressure Unit Conversion Problem Share Flipboard Email Print PSI and millibar are two common pressure units. Ryan Etter, Getty Images Science Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College 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. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated March 06, 2017 This example problem demonstrates how to convert the pressure unit pounds per square inch (psi) to millibars (mb).Problem:The average air pressure at sea level is 14.6 psi. What is this pressure in mbar?Solution:1 psi = 68.947 mbarSet up the conversion so the desired unit will be canceled out. In this case, we want mbar to be the remaining unit.pressure in mbar = (pressure in psi) x (68.947 mbar/1 psi)pressure in mbar = (14.6 x 68.947) mbarpressure in mbar = 1006.6 mbarAnswer:The average sea level air pressure is 1006.6 mbar.