Convert Pound per Square Inch to Inch of Mercury (psi → inHg)
PSI (pounds per square inch) is the standard for American tire pressures, hydraulics, and gas-cylinder specifications.
Pound per Square Inch to Inch of Mercury Conversion Table
10 common values| Pound per Square Inch | Inch of Mercury |
|---|---|
| 1 psi | 2.036021 inHg |
| 5 psi | 10.180102 inHg |
| 10 psi | 20.360205 inHg |
| 25 psi | 50.900512 inHg |
| 50 psi | 101.80102 inHg |
| 100 psi | 203.60205 inHg |
| 200 psi | 407.20409 inHg |
| 500 psi | 1,018.0102 inHg |
| 1,000 psi | 2,036.0205 inHg |
| 5,000 psi | 10,180.102 inHg |
How to Convert Pound per Square Inch to Inch of Mercury Manually
Step by StepConverting psi to inches of mercury is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.
- 1Take your value in psiStart with the number of psi (psi) you want to convert.
- 2Multiply by 2.036021The conversion factor from psi to inHg is 2.036021. Multiply your value by this number.
- 3Read the result in inches of mercuryThe result is your value in inches of mercury (inHg).
Formula
Multiply the value in psi by 2.036021. For the reverse direction, multiply by 0.491154.
inHg = psi × 2.036021psi = inHg × 0.491154Tips
Use these in everyday conversions- 1 psi ≈ 6.9 kPa = 0.069 bar.
- 14.7 psi = 1 atm = 1.01 bar.
- Most US pressure gauges show psi.
Common Mistakes
Avoid these- Setting a European tyre at 35 bar instead of 35 psi — disaster.
- Confusing psi (gauge) with psia (absolute).
- Using psi in scientific papers — prefer Pa or MPa.
About Pound per Square Inch and Inch of Mercury
What is the Pound per Square Inch?
Pounds per square inch (psi) equals approximately 6,895 pascals and is the standard pressure unit in American tire pressures, hydraulics, and gas-cylinder specifications. American car tires are typically inflated to 30–35 psi, household water systems run at 40–60 psi, and scuba tanks are filled to 3,000 psi (about 200 bar). The psi is essential in American engineering for stress calculations, hydraulic systems, and pneumatic equipment. Two variants exist: 'psig' (gauge, measured above atmospheric) and 'psia' (absolute, including atmosphere) — gauge is the default unless specified. The psi relates to the pascal (1 psi ≈ 6,895 Pa), the kilopascal (1 psi ≈ 6.895 kPa), the bar (14.504 psi = 1 bar), the atmosphere (14.696 psi = 1 atm), and the inch of mercury (1 inHg ≈ 0.491 psi). Outside the US, kPa or bar dominate.
- US tyre pressures
- US plumbing and water system specs
- US compressed-air tool ratings
US tyre: 32–35 psi. Water supply: 40–60 psi. SCUBA tank: 3000 psi. Car AC system: 30–200 psi.
What is the Inch of Mercury?
The inch of mercury equals exactly 25.4 mmHg (or about 3,386.4 pascals) and is the American aviation standard for altimeter settings and historic barometer readings. Pilots set their altimeters to the local atmospheric pressure in inHg before takeoff and landing — standard 'sea-level pressure' is 29.92 inHg. American weather reports historically used inHg before transitioning to millibars/hPa, and home barometers in the US still display inHg. The unit relates to the mmHg (25.4 mmHg = 1 inHg), the millibar (1 inHg ≈ 33.864 mbar), the kilopascal (1 inHg ≈ 3.386 kPa), and the psi (1 inHg ≈ 0.491 psi). Aviation's continued use of inHg in the United States reflects regulatory tradition rather than scientific advantage; international ATC outside the US uses hectopascals.
- US aviation altimeter QNH settings
- US residential barometers
- US weather forecasts (older)
Sea-level standard: 29.92 inHg. Mountain pass at 3000 m: ~21 inHg. US aviation QNH given in inHg.