Convert pressure units — pascal, PSI, bar, atmosphere, torr, mmHg and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 inHg | 0.0254001 mmHg | |
| 0.01 inHg | 0.254001 mmHg | |
| 0.1 inHg | 2.54001 mmHg | |
| 1 inHg | 25.4001 mmHg | |
| 5 inHg | 127 mmHg | |
| 10 inHg | 254.001 mmHg | |
| 50 inHg | 1270 mmHg | |
| 100 inHg | 2540.01 mmHg | |
| 1000 inHg | 25400.1 mmHg |
Formula: mmHg = Inch Hg × 25.4
Multiply any inch hg value by 25.4 to get mmhg.
Reverse: Inch Hg = mmHg × 0.03937
Common inch hg values — factor: 1 inHg = 25.4 mmHg
| Inch Hg (inHg) | mmHg (mmHg) | Context |
|---|---|---|
| 0.01 inHg | 0.254 mmHg | Near vacuum |
| 0.1 inHg | 2.54 mmHg | Very low |
| 1 inHg | 25.4 mmHg | Low pressure |
| 10 inHg | 254 mmHg | ~10 inHg |
| 20 inHg | 508 mmHg | ~20 inHg |
| 25 inHg | 635 mmHg | Low weather |
| 28 inHg | 711.2 mmHg | Hurricane center |
| 29 inHg | 736.6 mmHg | Storm low |
| 29.92 inHg | 760 mmHg | 1 standard atm |
| 30 inHg | 762 mmHg | Slightly high |
| 31 inHg | 787.4 mmHg | High pressure |
| 35 inHg | 889 mmHg | Very high |
| 50 inHg | 1,270 mmHg | ~1.67 atm |
| 100 inHg | 2,540 mmHg | ~3.34 atm |
| 1,000 inHg | 2.54e+04 mmHg | ~33.4 atm |
1 inHg = 25.4 mmHg. Memorize for instant estimates.
Use 25.4 as a quick mental multiplier.
Multiply result by 0.03937 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.
Millimeters of mercury (mmHg) is the traditional medical pressure unit, defined as the pressure exerted by a 1 mm column of mercury at 0°C under standard gravity. It equals 133.322 Pa and is numerically identical to the torr.
Blood pressure is universally measured in mmHg worldwide: normal blood pressure is about 120/80 mmHg. Intraocular pressure (glaucoma screening) is measured in mmHg. Gas partial pressures in physiology are quoted in mmHg.
Interesting fact: The sphygmomanometer (blood pressure cuff) still uses mmHg more than 130 years after its invention, making mmHg one of the most clinically important pressure units despite not being an SI unit.
Converting inch hg to mmhg 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 = 127 mmHg and 10 inHg = 254 mmHg. For the reverse: 1 mmHg = 0.03937 inHg. The exact factor is 1 inHg = 25.4 mmHg.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.