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Convert Inches of mercury to Kilopascals

1 inch of mercury is 3.386389 kPa. One inch of mercury is exactly 3.386389 kilopascals.

One inch of mercury is 3.386389 kilopascals. To convert inches of mercury to kilopascals, multiply by 3.386389; to go the other way, divide by 3.386389 or multiply by 0.2952998. 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

Kilopascals
3.386389 kPa
Inches of mercury × 3.386389
value * 3.3863893.386 kPa

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 kilopascals?

  1. 1.Take the measurement in inches of mercury.
  2. 2.Multiply by 3.386389 — that is how many kilopascals fit in one inch of mercury.
  3. 3.To go back the other way, divide by 3.386389, or multiply by 0.2952998.

Worked example: 25 inches of mercury to kilopascals

Formula
inHg × 3.386389 = kPa
Arithmetic
25 × 3.386389 = 84.659725 kPa
Answer
25 inHg = 84.659725 kPa

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

Inches of mercury to kilopascals conversion table

Inches of mercuryKilopascals
1 inHg3.386389 kPa
2 inHg6.772778 kPa
3 inHg10.159167 kPa
4 inHg13.545556 kPa
5 inHg16.931945 kPa
6 inHg20.318334 kPa
7 inHg23.704723 kPa
8 inHg27.091112 kPa
9 inHg30.477501 kPa
10 inHg33.86389 kPa
12 inHg40.636668 kPa
15 inHg50.795835 kPa
20 inHg67.72778 kPa
25 inHg84.659725 kPa
50 inHg169.31945 kPa
100 inHg338.6389 kPa
200 inHg677.2778 kPa
300 inHg1,015.9167 kPa
500 inHg1,693.1945 kPa
1000 inHg3,386.389 kPa
2000 inHg6,772.778 kPa
5000 inHg16,931.945 kPa
10000 inHg33,863.89 kPa

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 kilopascal?

A thousand pascals, and the unit metric tyre placards and weather stations use. Atmospheric pressure at sea level is about 101 kPa.

How many kilopascals are in an inch of mercury?

One inch of mercury is 3.386389 kilopascals, exactly. Going the other way, one kilopascal is 0.2952998 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 kilopascals are in an inch of mercury?
3.386389. A thousand pascals, and the unit metric tyre placards and weather stations use. Atmospheric pressure at sea level is about 101 kPa.
How do I convert kilopascals back to inches of mercury?
Divide by 3.386389, or multiply by 0.2952998 — they are the same operation.

Other pressure conversions

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