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: Atmosphere = Inch Hg × 0.03342
Multiply any inch hg value by 0.03342 to get atmosphere.
Reverse: Inch Hg = Atmosphere × 29.92
Common inch hg values — factor: 1 inHg = 0.03342 atm
| Inch Hg (inHg) | Atmosphere (atm) | Context |
|---|---|---|
| 0.01 inHg | 0.0003342 atm | Near vacuum |
| 0.1 inHg | 0.003342 atm | Very low |
| 1 inHg | 0.03342 atm | Low pressure |
| 10 inHg | 0.3342 atm | ~10 inHg |
| 20 inHg | 0.6684 atm | ~20 inHg |
| 25 inHg | 0.8355 atm | Low weather |
| 28 inHg | 0.9358 atm | Hurricane center |
| 29 inHg | 0.9692 atm | Storm low |
| 29.92 inHg | 1 atm | 1 standard atm |
| 30 inHg | 1.003 atm | Slightly high |
| 31 inHg | 1.036 atm | High pressure |
| 35 inHg | 1.17 atm | Very high |
| 50 inHg | 1.671 atm | ~1.67 atm |
| 100 inHg | 3.342 atm | ~3.34 atm |
| 1,000 inHg | 33.42 atm | ~33.4 atm |
1 inHg = 0.03342 atm. Memorize for instant estimates.
Use 0.0334 as a quick mental multiplier.
Multiply result by 29.92 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.
The atmosphere (atm) is defined as exactly 101,325 pascals — the approximate air pressure at sea level. It was originally defined as the average atmospheric pressure at sea level at 45° latitude, and has been a standard reference since the 17th century.
Atmospheres are used in chemistry (gas laws), scuba diving depth calculations (every 10 m of water ≈ 1 additional atm), and as a convenient reference for extreme pressure comparisons.
Interesting fact: Jupiter's atmosphere has pressures exceeding 1,000 atm at depth. Diamond formation in Earth's mantle requires pressures of 45,000–60,000 atm at depths of 150–200 km.
Converting inch hg to atmosphere 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 = 0.1671 atm and 10 inHg = 0.3342 atm. For the reverse: 1 atm = 29.92 inHg. The exact factor is 1 inHg = 0.03342 atm.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.