Pressure Converter
Solve pressure problems step-by-step with our free calculator. See formulas, worked examples, and clear explanations.
Reviewed by Manoj Kumar, Mathematics Educator
Formula
target = input * (input_toPa / target_toPa)
Pressure conversion works by converting the input value to pascals using the known conversion factor, then dividing by the target unit factor. For example, 1 atm = 101325 Pa, and 1 psi = 6894.757 Pa, so 1 atm = 101325/6894.757 = 14.696 psi.
Worked Examples
Example 1: Converting 1 Atmosphere to All Units
Problem:Convert standard atmospheric pressure (1 atm) to pascals, bar, PSI, Torr, and mmHg.
Solution:1 atm = 101,325 Pa\n1 atm = 1.01325 bar\n1 atm = 14.6960 psi\n1 atm = 760.0000 Torr\n1 atm = 760.0000 mmHg\n1 atm = 29.9213 inHg\n1 atm = 1013.25 mbar
Result:1 atm = 101325 Pa = 1.013 bar = 14.696 psi = 760 Torr
Example 2: Tire Pressure Conversion
Problem:A tire is inflated to 32 PSI. Convert to bar, kPa, and atmospheres.
Solution:32 PSI to Pa: 32 * 6894.757 = 220,632.2 Pa\nTo kPa: 220,632.2 / 1000 = 220.632 kPa\nTo bar: 220,632.2 / 100,000 = 2.2063 bar\nTo atm: 220,632.2 / 101,325 = 2.1776 atm
Result:32 PSI = 2.2063 bar = 220.632 kPa = 2.1776 atm
Frequently Asked Questions
What is pressure and how is it measured?
Pressure is defined as force per unit area, measured in pascals (Pa) in the SI system, where one pascal equals one newton per square meter. Pressure exists in many forms: atmospheric pressure from the weight of air above us, hydraulic pressure in fluid systems, gauge pressure in tires and pipes, and absolute pressure which includes atmospheric contribution. Standard atmospheric pressure at sea level is 101,325 Pa (1 atm). Pressure can be measured using manometers, barometers, Bourdon tube gauges, and piezoelectric sensors. Understanding pressure is essential in meteorology, engineering, medicine, diving, aviation, and countless industrial applications.
What is the difference between absolute and gauge pressure?
Absolute pressure is measured relative to a perfect vacuum (zero pressure), while gauge pressure is measured relative to atmospheric pressure. Gauge pressure equals absolute pressure minus atmospheric pressure. When a tire gauge reads 32 psi, that is gauge pressure; the absolute pressure inside the tire is actually about 46.7 psi (32 + 14.7 psi atmospheric). In engineering, gauge pressure is denoted with a 'g' suffix (psig) and absolute with an 'a' suffix (psia). Vacuum pressures are negative gauge pressures. Most everyday pressure measurements use gauge pressure, but thermodynamic calculations and gas law equations require absolute pressure to produce correct results.
What is standard atmospheric pressure and why does it matter?
Standard atmospheric pressure is defined as exactly 101,325 pascals (1 atm), which equals 1.01325 bar, 14.696 psi, 760 mmHg, or 29.921 inches of mercury. This value represents the average sea-level pressure and serves as a reference point throughout science and engineering. It matters because many physical and chemical properties are specified at standard pressure: boiling points, gas densities, and chemical equilibrium constants. Water boils at 100 degrees Celsius only at standard pressure; at higher altitudes where pressure is lower, water boils at lower temperatures. Standard pressure is also critical for aircraft altimeter calibration and weather forecasting.
What is a bar and how does it relate to other pressure units?
One bar equals exactly 100,000 pascals (100 kPa) and is very close to standard atmospheric pressure (1 atm = 1.01325 bar). The bar was introduced to provide a convenient metric unit close to atmospheric pressure without the awkwardness of expressing pressure in hundreds of thousands of pascals. The millibar (1/1000 of a bar = 100 Pa = 1 hectopascal) is the traditional unit for atmospheric pressure in meteorology and weather forecasts. Many European countries use bar for tire pressure and industrial applications. The bar is not an official SI unit but is accepted for use with the SI system, making it a practical bridge between scientific and everyday pressure measurements.
References
Reviewed by Manoj Kumar, Mathematics Educator · Editorial policy