mmHg to Pa Converter
The conventional millimetre of mercury is defined rather than measured: a millimetre of mercury at a density of 13,595.1 kg/m³ under a standard gravity of 9.80665 m/s², which multiplies out to exactly 133.322387415 pascals. So mmHg to Pa is one multiplication, Pa = mmHg × 133.322387415, landing in the SI unit of pressure, one newton per square metre. That makes 1 mmHg 133.322387415 Pa, 2 mmHg 266.64477483 Pa, 7.5 mmHg 999.917905613 Pa, 10 mmHg 1,333.22387415 Pa, 100 mmHg 13,332.2387415 Pa, 750 mmHg 99,991.7905613 Pa and 760 mmHg 101,325.014435 Pa, a shade over the 101,325 Pa of a standard atmosphere because 760 to the atmosphere defines the torr and not the conventional mmHg. This page opens the converter with mmHg in the From box and Pascal (Pa) in the To box, ahead of whatever pair you converted last, and the list under the answer carries the same pressure in kilopascals, bar, pounds per square inch and atmospheres, so 760 mmHg also reads 101.325014435 kPa, 1.01325014435 bar, 14.6959508692 psi and 1.00000014247 atm. It changes the units on a number and nothing else: what the figure describes is not something arithmetic can tell you.
1 mmHg in every pressure unit
Common questions
- How many pascals is 1 mmHg?
- Exactly 133.322387415 Pa, and the multiplication scales without any rounding of its own: 2 mmHg is 266.64477483 Pa, 5 mmHg is 666.611937075 Pa, 20 mmHg is 2,666.4477483 Pa, 100 mmHg is 13,332.2387415 Pa and 1,000 mmHg is 133,322.387415 Pa. Going down instead, 0.001 mmHg is 0.133322387415 Pa. Answers print to twelve significant digits, which is every digit this factor has.
- What is the formula for mmHg to Pa?
- Pascals = millimetres of mercury × 133.322387415, and millimetres of mercury = pascals / 133.322387415, which is the same as multiplying by 0.00750061575846. So 1 Pa is 0.00750061575846 mmHg, 1,000 Pa is 7.50061575846 mmHg and 100,000 Pa is 750.061575846 mmHg. The swap button between the two boxes reverses the pair, which turns this into a pascals to mmHg converter without a reload.
- Where does the number 133.322387415 come from?
- From three conventions multiplied together: a mercury density of 13,595.1 kg/m³, a standard gravity of 9.80665 m/s² and a height of one millimetre. Because all three are fixed by agreement rather than measured on the day, their product is exact and the unit does not drift. Real mercury is a different matter, since its density moves with temperature, so an actual mercury column and the conventional unit named after it are not quite the same thing.
- Is 760 mmHg exactly one atmosphere?
- Not quite. This page reads 760 mmHg as 101,325.014435 Pa, while a standard atmosphere is exactly 101,325 Pa, so the atmosphere is 759.999891726 mmHg. The 760 belongs to the torr, which is defined as 101,325 / 760 = 133.322368421 Pa exactly, about fourteen parts in a hundred million smaller than the conventional mmHg. The gap shows up at the eighth digit and never at the third.
- How do I convert kPa or bar to mmHg?
- Press the swap button and then pick the unit you have in the From menu, or read the rows under the answer. One kilopascal is 7.50061575846 mmHg, one bar is 750.061575846 mmHg, and 101.325 kPa comes back as 759.999891726 mmHg. In the other direction 760 mmHg is 101.325014435 kPa and 1.01325014435 bar, both of them listed the moment you type the figure.
- What about hectopascals and millibars, the units on a weather map?
- They are not separate rows, because each is a scaled pascal: 1 hPa is 100 Pa and is also exactly 1 mbar. So a hectopascal figure is the pascal answer with the decimal point moved two places to the left, and a millibar figure is the bar row with it moved three places to the right, which puts 760 mmHg at 1,013.25014435 hPa either way. The category itself holds pascals, kilopascals, bar, pounds per square inch, atmospheres and millimetres of mercury.
- Why does the list under the answer not repeat mmHg?
- The list shows every other unit in the category and skips the one you are converting from, so here it reads pascals, kilopascals, bar, pounds per square inch and atmospheres, with the pascal figure appearing both in the headline and as a row. The readout strip also carries an Uncommon units switch labelled Show 1 more, because mmHg is the one uncommon pressure unit; on this page turning it on changes nothing you can see, since the unit it would add is already in the From box.
- Why does the page open on mmHg and Pa when I last converted something else?
- Because a page that names a pair should show that pair. This one sets millimetres of mercury and pascals on arrival, ahead of whatever the converter last remembered, and it leaves the main unit converter's own pair alone: go back there and it is still on the units you left it on. The number you last typed does travel with you, along with the uncommon units switch, since that is usually the figure you are still working on.
Conversion factors are the exact legal definitions where one exists. An inch is exactly 2.54 cm and a pound exactly 0.45359237 kg, so those conversions are exact rather than approximate. Temperature uses offsets rather than factors, and that is shown in the working.