Convert Inches of Mercury to psi
1 inch of mercury (inHg) equals 0.4911541475 psi.
1 inHg = 0.4911541475 psi
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk inch of mercury to psi converter to paste a column from Excel.
How to Convert Inch of Mercury to psi
- 1 inHg = 0.4911541475 psi
- 1 psi = 2.036020677 inHg
- Example: convert 15 inHg to psi: 15 inHg = 15 × 0.4911541475 psi = 7.367312212 psi
Reference conditions. inHg: Conventional mercury column: ρ = 13 595.1 kg/m³ and gₙ = 9.80665 m/s² (≈ mercury at 0 °C / 32 °F).
Formula
psi = inHg × 0.4911541474703
or psi = inHg ÷ 2.036020677318
Derivation from SI units:
- 1 inHg = 13 595.1 kg/m³ × 9.80665 m/s² × 0.0254 m = 3386.388640341 Pa
- 1 psi = 1 lbf/in² = (0.45359237 kg × 9.80665 m/s²) ÷ (0.0254 m)² = 6894.757293168 Pa
- 1 inHg = 3386.388640341 Pa ÷ 6894.757293168 Pa per psi = 0.4911541474703 psi
Both units are defined exactly, so the factor is exact. Inch of Mercury definition: inch of mercury; psi definition: psi.
Worked examples
- The standard altimeter setting, 29.92 inHg, is 14.69533209 psi.
29.92 inHg × 0.4911541475 = 14.69533209 psi - A vacuum of 25 inHg corresponds to 12.27885369 psi.
25 inHg × 0.4911541475 = 12.27885369 psi
Inch of Mercury to psi conversion table
| Inches of Mercury (inHg) | psi |
|---|---|
| 0.5 inHg | 0.2455770737 psi |
| 1 inHg | 0.4911541475 psi |
| 2 inHg | 0.9823082949 psi |
| 5 inHg | 2.455770737 psi |
| 10 inHg | 4.911541475 psi |
| 15 inHg | 7.367312212 psi |
| 20 inHg | 9.823082949 psi |
| 25 inHg | 12.27885369 psi |
| 28 inHg | 13.75231613 psi |
| 28.5 inHg | 13.9978932 psi |
| 29 inHg | 14.24347028 psi |
| 29.5 inHg | 14.48904735 psi |
| 29.92 inHg | 14.69533209 psi |
| 30 inHg | 14.73462442 psi |
| 30.5 inHg | 14.9802015 psi |
| 31 inHg | 15.22577857 psi |
Where it's used
Altimeter settings, barometers and vacuum gauges in inHg are converted to psi for engine, cabin-pressure and vacuum-system calculations.
Inch of Mercury to other pressure units
| Conversion | 1 inHg equals |
|---|---|
| inch of mercury to pascal | 3386.38864 Pa |
| inch of mercury to kilopascal | 3.38638864 kPa |
| inch of mercury to megapascal | 0.00338638864 MPa |
| inch of mercury to psi | 0.4911541475 psi |
| inch of mercury to bar | 0.0338638864 bar |
| inch of mercury to millibar | 33.8638864 mbar |
| inch of mercury to decibar | 0.338638864 dbar |
| inch of mercury to torr | 25.40000362 Torr |
| inch of mercury to millimeter of mercury | 25.4 mmHg |
| inch of mercury to millimeter of water | 345.31554 mmH₂O |
| inch of mercury to centimeter of water | 34.531554 cmH₂O |
| inch of mercury to inch of water | 13.5951 inH₂O |
| inch of mercury to inch of water (60 °F) | 13.60869892 inH₂O (60 °F) |
| inch of mercury to atmosphere | 0.03342105739 atm |
| inch of mercury to barye | 33863.8864 Ba |
Frequently asked questions
What is 29.92 inHg in psi?
29.92 inHg = 14.7 psi, one standard atmosphere to four significant figures.
How many psi are in 1 inch of mercury?
1 inHg = 0.4911541475 psi.
How do I convert inches of mercury to psi?
Multiply the value in inHg by 0.4911541475, or divide it by 2.036020677. For example, 15 inHg × 0.4911541475 = 7.367312212 psi.
Is the inHg to psi conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "inch of mercury, conventional (inHg)".
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "pound-force per square inch (psi)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Inches of Mercury to psi. Retrieved October 17, 2026, from https://scientificconverters.com/pressure/inch-of-mercury-to-psi/
IEEE
Scientific Converters, "Convert Inches of Mercury to psi," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/pressure/inch-of-mercury-to-psi/