Hobbies Cars & Motorcycles What Is PSI? Share PINTEREST Email Print Ian Lishman / Getty Images Cars & Motorcycles Cars Basics Buying & Selling How Tos Reviews Tools & Products Classic Cars Exotic Cars Corvettes Mustangs Tires & Wheels Motorcycles Used Cars SUVs Trucks ATVs & Off Road Public Transportation By Christine & Scott Gable Automotive Writers B.S.E, Art Education, Millersville University Christine and Scott Gable are hybrid auto and alternative fuel experts who brewed biodiesel and traveled 125,000 miles on waste vegetable oil. our editorial process Christine & Scott Gable Updated May 09, 2019 The acronym PSI stands for "Pounds per Square Inch," and is the common unit of measurement for pressure. It can be understood as the amount of force that is exerted on an area of one square inch. Normal atmospheric pressure at sea level is 14.7 PSI. Pronunciation: Pronounce each letter individually: P - S - I. Example: Normal tire pressure is usually about 32 PSI.