PSI to Hectopascals (psi to hPa)
1 pound per square inch equals 68.94757293 hectopascals (rounded).
How to convert pounds per square inch to hectopascals
To convert pounds per square inch to hectopascals, multiply the number of pounds per square inch by 68.94757293. The factor is rounded to 10 significant digits. To go the other way, multiply hectopascals by 0.01450377377 (rounded).
hectopascals = pounds per square inch × 68.94757293
Example: 10 pounds per square inch = 689.4757293 hectopascals.
About these units
Pound Per Square Inch (psi)
About 6,894.757 pascals. The common unit for tire pressure, hydraulics and gas pipelines in the US.
Unlike most pressure units, psi has no namesake: it simply spells out its own definition, one pound-force acting on one square inch, and it is based on avoirdupois units. Used mainly in the United States, it is about 6.895 kilopascals.
The letters after the unit matter. Psia is measured against a vacuum, while psig is measured against the surrounding air, so at sea level, where the atmosphere is about 14.7 psi, you add that amount to a gauge reading to get an absolute one. A bicycle tire at 65 psig is therefore at 79.7 psia, and the label psid means a difference between two pressures rather than a reference to ambient air.
Typical automobile tires are listed at about 32 psig, and road racing bicycle tires at about 120 psig. One standard atmosphere is 14.696 psi, which gives a feel for how many multiples of sea-level air those tire pressures represent.
1 pound per square inch = 6,894.757293 pascals (approximately).
Sources: Wikipedia: Pounds per square inch; Wikipedia: Standard atmosphere (unit)
Hectopascal (hPa)
100 pascals, equal to one millibar. The standard unit in weather forecasts and barometers.
Weather forecasters rarely think in pascals, and the hectopascal exists largely to avoid changing their numbers. When SI arrived, meteorologists generally switched from the millibar to the hectopascal, which equals exactly 100 Pa and exactly one millibar, so existing readings carried over unchanged. Observations are typically reported in hPa, following the World Meteorological Organization recommendation, though many scientific fields dislike the hecto prefix because they prefer steps of 1,000.
A typical sea-level reading is about 1,013 hPa. The lowest non-tornadic pressure ever measured was 870 hPa, in Typhoon Tip on 12 October 1979, and the highest sea-level pressure, 1,084.8 hPa, came at Tosontsengel, Mongolia, on 19 December 2001, at a station above 750 meters. At low altitudes, pressure drops about 12 hPa for every 100 meters you climb.
Aviation weather reports, such as the QNH in a METAR, use hectopascals or millibars in most countries, while the US, Canada and Japan quote altimeter settings in inches of mercury.
1 hectopascal = 100 pascals (exactly).
Sources: Wikipedia: Hectopascal; Wikipedia: Atmospheric pressure; Wikipedia: Pascal (unit)
Related conversions
- Hectopascals to PSI (reverse)
- PSI to pascals
- PSI to kilopascals
- PSI to bars
- PSI to standard atmospheres
- PSI to megapascals
- PSI to millibars
- PSI to torr
- PSI to millimeters of mercury
- PSI to inches of mercury
- PSI to gigapascals
- PSI to kilopounds per square inch
- PSI to millimeters of water
- Pascals to hectopascals
- Kilopascals to hectopascals
- Bars to hectopascals
- Standard atmospheres to hectopascals
- Megapascals to hectopascals
- Millibars to hectopascals
- Torr to hectopascals
- Millimeters of mercury to hectopascals
- Inches of mercury to hectopascals
See all pressure units.