Convert pressure units — Pascal, bar, PSI, atm, Torr, mmHg.
| Unit | Name | Value |
|---|---|---|
| Pa | Pascal | 3386.39 |
| kPa | Kilopascal | 3.38639 |
| bar | Bar | 0.0338639 |
| atm | Atmosphere | 0.033421071 |
| psi | PSI | 0.49115415 |
| Torr | Torr / mmHg | 25.400084 |
Formula: PSI = Inch Hg × 0.4912
Multiply any inch hg value by 0.4912 to get psi.
Reverse: Inch Hg = PSI × 2.036
Common inch hg values — factor: 1 inHg = 0.4912 psi
| Inch Hg (inHg) | PSI (psi) | Context |
|---|---|---|
| 0.01 inHg | 0.004912 psi | Near vacuum |
| 0.1 inHg | 0.04912 psi | Very low |
| 1 inHg | 0.4912 psi | Low pressure |
| 10 inHg | 4.912 psi | ~10 inHg |
| 20 inHg | 9.823 psi | ~20 inHg |
| 25 inHg | 12.28 psi | Low weather |
| 28 inHg | 13.75 psi | Hurricane center |
| 29 inHg | 14.24 psi | Storm low |
| 29.92 inHg | 14.7 psi | 1 standard atm |
| 30 inHg | 14.73 psi | Slightly high |
| 31 inHg | 15.23 psi | High pressure |
| 35 inHg | 17.19 psi | Very high |
| 50 inHg | 24.56 psi | ~1.67 atm |
| 100 inHg | 49.12 psi | ~3.34 atm |
| 1,000 inHg | 491.2 psi | ~33.4 atm |
1 inHg = 0.4912 psi. Memorize for instant estimates.
Use 0.4912 as a quick mental multiplier.
Multiply result by 2.036 to recover the original inHg value.
Sets altimeter QNH and reads weather ATIS in inHg — standard US aviation.
Reports barometric pressure in inHg for US television and radio weather.
Measures duct static pressure in inches of water column or inHg in US systems.
Checks HVAC system static pressure and duct leakage in inHg.
Logs surface pressure in inHg for propagation prediction and wx stations.
References inHg barometric pressure when using US-spec nautical instruments.
Inches of mercury (inHg) is the pressure unit used in US aviation and weather reporting, defined as the pressure exerted by a 1-inch column of mercury (3,386.39 Pa). It has been standard in US aviation since the early 20th century.
US aviation altimeters are set in inHg (standard: 29.92 inHg). US weather broadcasts report barometric pressure in inHg. HVAC engineers in the US use inHg for duct static pressure measurements.
Interesting fact: Pilots set their altimeter to the local QNH (pressure at sea level) in inHg to ensure their altitude reading is accurate — a difference of 0.1 inHg causes an altimeter error of about 100 feet.
PSI (pounds per square inch) is the primary pressure unit in the United States, UK, and other countries using Imperial measures. It equals the force of one pound-force applied over one square inch of area (6,894.76 Pa).
PSI is used for tire pressure (car: 30–35 psi, truck: 80–120 psi), blood pressure measurement in the US, boiler pressure ratings, and hydraulic system specifications in American engineering.
Interesting fact: The deepest ocean dive by a human (Victor Vescovo, 2019, 10,928 m) would have experienced about 15,900 psi of external pressure on the submersible hull.
Converting inch hg to psi is a common task in engineering, medicine, meteorology, and science. Different industries and countries use different pressure units — PSI in the US, bar in Europe, mmHg in medicine, and pascals in physics — making accurate conversion essential for cross-disciplinary work.
Quick reference: 5 inHg = 2.456 psi and 10 inHg = 4.912 psi. For the reverse: 1 psi = 2.036 inHg. The exact factor is 1 inHg = 0.4912 psi.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.