Millimeter Mercury to Atmosphere Converter

Millimeters of mercury, written mmHg, and standard atmospheres, written atm, are units of pressure. The mmHg unit originated with mercury barometers, where pressure was represented by the height of a mercury column. Standard atmosphere is a defined reference pressure used in science and engineering. The familiar relationship is 760 mmHg for one standard atmosphere, so this calculator divides the entered mmHg value by 760 to produce atmospheres. The converter also presents pascals, bar, and pounds per square inch for convenient comparison. One standard atmosphere equals exactly 101,325 pascals and 1.01325 bar, and it is approximately 14.6959487755 pounds per square inch. Once the atmosphere value is known, multiplying by these factors supplies the additional outputs. At 760 mmHg, for example, the results are 1 atm, 101,325 Pa, 1.01325 bar, and about 14.696 psi. Millimeters of mercury remain common in medicine, meteorology, vacuum measurement, and laboratory work. Blood pressure is conventionally reported in mmHg, with systolic and diastolic readings such as 120 and 80. Barometric pressure may also appear in mmHg, although weather services frequently use hectopascals or inches of mercury. Atmospheres are useful for comparing a pressure with a standard sea-level reference, while pascals are the SI unit preferred in many technical calculations. A unit conversion does not change the reference basis of a pressure measurement. Absolute pressure is measured relative to a vacuum, while gauge pressure is measured relative to surrounding atmospheric pressure. A value must keep its original basis after conversion. Temperature, instrument calibration, local altitude, and measurement uncertainty may also matter in practical applications, even when the numerical conversion factor is applied correctly. Use this converter to compare medical readings, laboratory data, barometer values, vacuum specifications, or engineering documentation. Enter a non-negative mmHg value and select the conversion button. The main result gives atmospheres, while the supporting cards give other widely used units. Preserve only as many significant figures as the source measurement supports, especially when documenting experimental or safety-related results.