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Convert Inches of mercury to Pascals

1 inch of mercury is 3,386.389 Pa. One inch of mercury is exactly 3386.389 pascals.

One inch of mercury is 3386.389 pascals. To convert inches of mercury to pascals, multiply by 3386.389; to go the other way, divide by 3386.389 or multiply by 2.9530 × 10^-4. The factor is exact rather than rounded: it follows from NIST Special Publication 811. The pressure of a one-inch column of mercury at 0 °C, fixed by convention at 3,386.389 pascals.

Factor checked against the defining standard · How we check

Pascals
3,386.389 Pa
Inches of mercury × 3386.389
value * 3386.3893,386.389 Pa

1 inch of mercury in every pressure unit

UnitValueExact factor
pounds per square inch0.4911541996 psi× 0.491154199634
bars0.03386389 bar× 0.03386389
pascals3,386.389 Pa× 3,386.389
kilopascals3.386389 kPa× 3.386389
megapascals0.003386389 MPa× 0.003386389
atmospheres0.03342106094 atm× 0.0334210609425
torr25.40000632 Torr× 25.4000063163
inches of mercury (as entered)1 inHg

Factors are entered by hand from NIST Special Publication 811 rather than derived from a units library, so the ones that terminate are exact rather than rounded.

How do you convert inches of mercury to pascals?

  1. 1.Take the measurement in inches of mercury.
  2. 2.Multiply by 3386.389 — that is how many pascals fit in one inch of mercury.
  3. 3.To go back the other way, divide by 3386.389, or multiply by 2.9530 × 10^-4.

Worked example: 25 inches of mercury to pascals

Formula
inHg × 3386.389 = Pa
Arithmetic
25 × 3386.389 = 84,659.725 Pa
Answer
25 inHg = 84,659.725 Pa

The factor is exact, so this figure is exact too — only the display is rounded.

Inches of mercury to pascals conversion table

Inches of mercuryPascals
1 inHg3,386.389 Pa
2 inHg6,772.778 Pa
3 inHg10,159.167 Pa
4 inHg13,545.556 Pa
5 inHg16,931.945 Pa
6 inHg20,318.334 Pa
7 inHg23,704.723 Pa
8 inHg27,091.112 Pa
9 inHg30,477.501 Pa
10 inHg33,863.89 Pa
12 inHg40,636.668 Pa
15 inHg50,795.835 Pa
20 inHg67,727.78 Pa
25 inHg84,659.725 Pa
50 inHg169,319.45 Pa
100 inHg338,638.9 Pa
200 inHg677,277.8 Pa
300 inHg1,015,916.7 Pa
500 inHg1,693,194.5 Pa
1000 inHg3,386,389 Pa
2000 inHg6,772,778 Pa
5000 inHg16,931,945 Pa
10000 inHg33,863,890 Pa

What is an inch of mercury?

The pressure of a one-inch column of mercury at 0 °C, fixed by convention at 3,386.389 pascals. US aviation altimeters and barometers read in it.

What is a pascal?

The SI unit: one newton spread over one square metre. It is a small pressure — a sheet of paper resting on a table is about one pascal — which is why the kilopascal is what instruments actually read.

How many pascals are in an inch of mercury?

One inch of mercury is 3386.389 pascals, exactly. Going the other way, one pascal is 2.9530 × 10^-4 inches of mercury. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.

Every pressure unit here

UnitSymbolOne of these is
Pounds per square inchpsi6894.7573 pascal
Barsbar100000 pascal
PascalsPathe base unit
KilopascalskPa1000 pascal
MegapascalsMPa1000000 pascal
Atmospheresatm101325 pascal
TorrTorr133.32237 pascal
Inches of mercuryinHg3386.389 pascal

Source: NIST Special Publication 811 — pound-force is exactly 4.4482216152605 N and the inch exactly 0.0254 m

Questions people actually ask

How many pascals are in an inch of mercury?
3386.389. The SI unit: one newton spread over one square metre. It is a small pressure — a sheet of paper resting on a table is about one pascal — which is why the kilopascal is what instruments actually read.
How do I convert pascals back to inches of mercury?
Divide by 3386.389, or multiply by 2.9530 × 10^-4 — they are the same operation.

Other pressure conversions

Pascals to inches of mercury — the same conversion the other way.