How many pascals are in one atmosphere?

One standard atmosphere equals exactly 101,325 pascals, or 101.325 kilopascals. It is also equal to 1.01325 bar, 14.6959 psi, and 760 mmHg.

What is the difference between bar and psi?

One bar equals 100,000 pascals, while one psi equals 6,894.757 pascals. To convert bar to psi multiply by 14.5038. One standard atmosphere is about 1.01325 bar or 14.696 psi.

What does mmHg measure?

Millimetres of mercury (mmHg) measures pressure as the height of a mercury column the pressure would support. One mmHg equals 133.322 pascals and one standard atmosphere equals 760 mmHg.

Pressure Converter

This pressure converter lets you switch between the most common pressure units instantly: pascals (Pa), kilopascals (kPa), megapascals (MPa), bar, pounds per square inch (psi), standard atmospheres (atm), millimetres of mercury (mmHg), and inches of mercury (inHg). Pressure measures the force applied per unit of area, and the same physical pressure can be expressed in very different numerical values depending on which unit you use. One standard atmosphere, for example, is 101,325 Pa, 101.325 kPa, approximately 14.696 psi, and 760 mmHg all at the same time. Engineers working with hydraulics or compressed air typically use bar or kPa; tyre pressures are quoted in psi or kPa depending on your region; barometric weather pressure is reported in hPa; and medical blood pressure is always given in mmHg. The SI unit is the pascal, so this converter uses pascals as its internal reference: all input values are converted to Pa first using a fixed factor, and every output unit is then derived from that single Pa figure. You select the unit you are starting from, enter a value, and all seven other equivalents appear immediately. This tool suits engineers, scientists, students, mechanics, divers, pilots, meteorologists, and anyone who needs to cross-check a pressure reading against a specification in a different unit. The conversion factors are based on internationally recognised definitions and do not change with temperature or altitude.

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From unit

Value to convert

101.3250

kilopascals (kPa)

Pa101325.0000

MPa0.101325

bar1.0133

psi14.6959

atm1.0000

mmHg760.0021

inHg29.9213

How it works

Every pressure unit has an exact conversion factor to pascals. The converter multiplies your input by that factor to get the pressure in Pa, then divides by each output unit factor to produce all results simultaneously. The factors used are: 1 kPa = 1,000 Pa; 1 MPa = 1,000,000 Pa; 1 bar = 100,000 Pa; 1 psi = 6,894.757 Pa; 1 atm = 101,325 Pa (exact by definition); 1 mmHg = 133.322 Pa; 1 inHg = 3,386.389 Pa. Because all factors are constants, the conversion is exact within floating-point precision.

Worked example

Starting from 1 atm: 1 times 101,325 gives 101,325 Pa, which equals 101.325 kPa. Dividing 101,325 by 6,894.757 gives 14.696 psi. Dividing by 133.322 gives 760.00 mmHg. These match the default values pre-filled in the converter above, so you can verify each output without changing anything.

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