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What is a inch of mercury?

The US aviation altimeter unit — 3386 Pa per inch

Definition

The inch of mercury equals about 3386 Pa. Used in US barometers, US aviation altimeter settings and some engineering. Standard sea-level pressure: 29.92 inHg.

Common uses

  • US aviation altimeter QNH settings
  • US residential barometers
  • US weather forecasts (older)

🌍 Real-world scale

Sea-level standard: 29.92 inHg. Mountain pass at 3000 m: ~21 inHg. US aviation QNH given in inHg.

Convert from inches of mercury

9 conversions
Inch of Mercury to Pascal1 inHg = 3,386.39 PaInch of Mercury to Kilopascal1 inHg = 3.38639 kPaInch of Mercury to Megapascal1 inHg = 0.003386 MPaInch of Mercury to Bar1 inHg = 0.03386 barInch of Mercury to Millibar1 inHg = 33.8639 mbarInch of Mercury to Pound per Square Inch1 inHg = 0.4912 psiInch of Mercury to Atmosphere1 inHg = 0.03342 atmInch of Mercury to Millimeter of Mercury1 inHg = 25.4 mmHgInch of Mercury to Torr1 inHg = 25.4 Torr

Convert to inches of mercury

9 conversions
Pascal to Inch of Mercury1 Pa = 0.0002953 inHgKilopascal to Inch of Mercury1 kPa = 0.2953 inHgMegapascal to Inch of Mercury1 MPa = 295.3 inHgBar to Inch of Mercury1 bar = 29.53 inHgMillibar to Inch of Mercury1 mbar = 0.02953 inHgPound per Square Inch to Inch of Mercury1 psi = 2.03602 inHgAtmosphere to Inch of Mercury1 atm = 29.9213 inHgMillimeter of Mercury to Inch of Mercury1 mmHg = 0.03937 inHgTorr to Inch of Mercury1 Torr = 0.03937 inHg

Tips

  • 1 inHg ≈ 3386 Pa ≈ 33.86 mbar.
  • 29.92 inHg = 1013.25 mbar = 1 atm.
  • US pilots use inHg; European pilots use hPa (mbar).

Common mistakes

  • Confusing inHg with mmHg — factor of 25.4.
  • Mixing US and European altimeter units on a single flight plan.
  • Using inHg on scientific papers — prefer Pa.

FAQ about the inch of mercury

What is a inch of mercury?
The inch of mercury equals about 3386 Pa. Used in US barometers, US aviation altimeter settings and some engineering. Standard sea-level pressure: 29.92 inHg.
Where is the inch of mercury used?
The inch of mercury is commonly used for: US aviation altimeter QNH settings; US residential barometers; US weather forecasts (older).
What is an example of a inch of mercury in real life?
Sea-level standard: 29.92 inHg. Mountain pass at 3000 m: ~21 inHg. US aviation QNH given in inHg.
What category does the inch of mercury belong to?
The inch of mercury is a unit of pressure, part of the 10-unit pressure category on UnitConv.
How accurate are inch of mercury conversions?
All conversion factors follow NIST and BIPM international standards to 8 significant figures — the highest practical accuracy.
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