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: Kilopascal = Inch Hg × 3.386
Multiply any inch hg value by 3.386 to get kilopascal.
Reverse: Inch Hg = Kilopascal × 0.2953
Common inch hg values — factor: 1 inHg = 3.386 kPa
| Inch Hg (inHg) | Kilopascal (kPa) | Context |
|---|---|---|
| 0.01 inHg | 0.03386 kPa | Near vacuum |
| 0.1 inHg | 0.3386 kPa | Very low |
| 1 inHg | 3.386 kPa | Low pressure |
| 10 inHg | 33.86 kPa | ~10 inHg |
| 20 inHg | 67.73 kPa | ~20 inHg |
| 25 inHg | 84.66 kPa | Low weather |
| 28 inHg | 94.82 kPa | Hurricane center |
| 29 inHg | 98.21 kPa | Storm low |
| 29.92 inHg | 101.3 kPa | 1 standard atm |
| 30 inHg | 101.6 kPa | Slightly high |
| 31 inHg | 105 kPa | High pressure |
| 35 inHg | 118.5 kPa | Very high |
| 50 inHg | 169.3 kPa | ~1.67 atm |
| 100 inHg | 338.6 kPa | ~3.34 atm |
| 1,000 inHg | 3,386 kPa | ~33.4 atm |
inHg × 3.386 = kPa. Round to × 3.39.
Standard atmosphere — US aviation anchor.
kPa ÷ 3.386 = inHg.
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.
The kilopascal (kPa) equals 1,000 pascals and is the practical everyday pressure unit in metric countries. It is the standard unit for tire pressure, blood pressure, and weather maps in countries using SI.
Blood pressure in many countries is expressed in kPa (normal: ~16/10.7 kPa), though mmHg remains dominant in medicine. Car tire pressure is typically 200–250 kPa. Weather maps use hPa (= mbar) for atmospheric pressure.
Interesting fact: The 'bends' (decompression sickness) in scuba diving occurs when dissolved nitrogen forms bubbles as pressure drops — a drop of just a few kPa too quickly can be fatal.
Converting inch hg to kilopascal 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 = 16.93 kPa and 10 inHg = 33.86 kPa. For the reverse: 1 kPa = 0.2953 inHg. The exact factor is 1 inHg = 3.386 kPa.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.