Pa to Atm Converter

Common questions

How many atm is 1 Pa?

0.00000986923266716 atm, which is 1 / 101,325. The pattern scales straight up: 1,000 Pa is 0.00986923266716 atm, 10,000 Pa is 0.0986923266716 atm, 50,000 Pa is 0.493461633358 atm, 100,000 Pa is 0.986923266716 atm and 101,325 Pa is exactly 1 atm. Answers are printed to twelve significant digits, so a long division is rounded for display rather than shown to the last place.

What is the formula for Pa to atm?

Atmospheres = pascals / 101,325, and pascals = atmospheres × 101,325 in the other direction. The 101,325 is a definition: the 10th General Conference on Weights and Measures fixed one standard atmosphere at exactly 101,325 Pa in 1954, so this factor is defined rather than measured. The division itself runs in binary floating point and the answer is shown to twelve significant digits, which is why 1 Pa prints as 0.00000986923266716. The Swap units button between the two boxes reverses the pair, so this page turns into an atm to Pa converter without a reload.

Is one bar the same as one atmosphere?

No, and the gap is about 1.31 percent. A bar is exactly 100,000 Pa, so it is 100,000 / 101,325 = 0.986923266716 atm, and one atmosphere is 1.01325 bar. Bar sits in the unit list on this page, so typing 100000 into the From box shows 1 bar and 0.986923266716 atm on the same screen, which is the quickest way to see that the two units are close but not interchangeable.

What is 1 atm in kPa and psi?

101.325 kPa and 14.6959487755 psi. Type 101325 with pascals selected and the list under the answer reads 101.325 kPa, 1.01325 bar, 14.6959487755 psi and 1 atm, because the converter works out every pressure unit at once rather than one target at a time. The psi figure follows from a pound per square inch being 6,894.757293168 Pa: 101,325 / 6,894.757293168 = 14.6959487755.

Is one atmosphere exactly 760 mmHg?

Exactly 760 torr, yes, because a torr is defined as one seven hundred and sixtieth of an atmosphere, or 101,325 / 760 pascals. The millimetre of mercury in this converter is the conventional mmHg of 133.322387415 Pa, which is a hair larger than a torr, so 101,325 Pa reads 759.999891726 mmHg rather than a round 760. Millimetres of mercury are hidden until you turn on the Uncommon units switch in the readout strip, labelled Show 1 more.

How do I convert megapascals to atmospheres here?

Type the value in pascals, since there is no megapascal entry in the list: 1 MPa is 1,000,000 Pa, which the converter shows as 9.86923266716 atm. The pressure category here holds pascals, kilopascals, bar, pounds per square inch and atmospheres, plus millimetres of mercury behind the uncommon units switch, so multiply megapascals by a million and enter that number.

Does it matter whether my reading is gauge or absolute?

It matters for what the number means, and the converter cannot tell which one you typed: it changes units and nothing else, so it never adds or removes an atmosphere on your behalf. A gauge sitting at zero is at roughly one atmosphere absolute, so a gauge reading of 200,000 Pa is 1.97384653343 atm above ambient, while the same pressure stated absolutely is 301,325 Pa, or 2.97384653343 atm. Settle which convention your figure uses before converting it.

Why does the page open on pascals and atmospheres when I last converted something else?

Because a page that names a pair should show that pair. This one sets pascals and atmospheres on arrival, ahead of whatever the converter last remembered, and it leaves the main unit converter's own memory alone: go back there and it is still on the pair you left it on. The number you last typed does come with you, since it is usually the one you are still working on.