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.
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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