How do I convert hPa to PSI?

Formula : PSI = hPa × 0.0145 Examples : 1,013 hPa = 14.7 PSI (sea level) 1,000 hPa = 14.5 PSI 900 hPa = 13.05 PSI 800 hPa = 11.6 PSI hPa to PSI converter →

Is hPa the same as mbar?

Yes, exactly! 1 hPa = 1 mbar Why two names? : Millibar (mbar) : Traditional meteorology unit (1900s-1980s) Hectopascal (hPa) : SI-compliant name (1980s-present) Same value, just renamed for SI consistency Conversion : None needed! They're identical. Modern usage : Weather services worldwide now use hPa, but many pilots and mariners still say "millibar."

What is normal atmospheric pressure in hPa?

Standard sea level : 1,013.25 hPa (exactly, by definition) Typical range : 980-1,050 hPa depending on weather Pressure variations : Fair weather (high) : 1,020-1,040 hPa Normal range : 1,000-1,020 hPa Stormy (low) : 980-1,000 hPa Hurricane : <980 hPa Regional/seasonal : Varies ±30 hPa from standard

How does pressure change with altitude?

Rough approximation : Pressure decreases ~12 hPa per 100m near sea level More accurate (ISA model): Altitude Pressure (hPa) % of Sea Level 0m 1,013 100% 500m 955 94% 1,000m 899 89% 2,000m 795 78% 3,000m 701 69% 5,000m 540 53% 8,848m (Everest) 313 31% Formula (approximate): P = 1013 × (1 - altitude/44,300)^5.255

What hPa is considered high or low pressure?

High pressure (anticyclone) : Strong high : >1,030 hPa (stable, clear weather) Moderate high : 1,020-1,030 hPa (fair weather) Normal pressure : 1,005-1,020 hPa Low pressure (cyclone) : Moderate low : 990-1,005 hPa (cloudy, possible rain) Strong low : 970-990 hPa (rain, wind) Very low : <970 hPa (storms, gales) Extreme low : <920 hPa (major hurricanes/typhoons) Context : Depends on region and season. 1,000 hPa may be "low" in winter anticyclone, "high" in tropical region.

Hectopascal (hPa) - Unit Information & Conversion

Symbol:hPa

Plural:hectopascals

Category:Pressure

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What is a Hectopascal?

Hectopascal (hPa) = 100 pascals. Standard unit for atmospheric pressure in meteorology. 1 hPa = 1 millibar exactly. Sea level pressure: ~1013 hPa. Used worldwide for weather reports, aviation altimetry.

History of the Hectopascal

Adopted by meteorologists in 1980s to replace millibar while transitioning to SI units. Convenient because 1 hPa = 1 mbar exactly, allowing seamless transition. Now standard for weather services globally (WMO recommendation).

Quick Answer

What is a Hectopascal? Hectopascal (hPa) = 100 pascals = 1 millibar exactly. Standard unit for atmospheric pressure in weather forecasts. Sea level: ~1013 hPa. High pressure: >1020 hPa (fair weather). Low pressure: <1000 hPa (storms). Use our pressure converter for conversions.

Definition

1 hPa = 100 Pa = 0.1 kPa = 1 mbar (exactly) = 0.001 bar = 0.0145 PSI = 0.000987 atm = 0.75 mmHg

Common Uses

Meteorology: Weather forecasts, atmospheric pressure reporting (worldwide standard). Aviation: Altimeter settings, flight level pressure (ICAO standard). Oceanography: Atmospheric pressure corrections for sea level measurements. Climatology: Historical pressure data, pressure trends.

Real-World Examples

Weather System Pressures

Very high pressure: 1,040-1,050 hPa (anticyclone, clear weather)
High pressure system: 1,020-1,035 hPa (fair weather)
Average sea level: 1,013.25 hPa (standard atmosphere)
Low pressure system: 980-1,000 hPa (cloudy, rain)
Storm: 960-980 hPa (strong low pressure)
Hurricane (Category 1): 980-990 hPa
Hurricane (Category 3): 945-965 hPa
Hurricane (Category 5): <920 hPa
Strongest hurricane: 882 hPa (Typhoon Tip, 1979)

Altitude Pressure (ISA Standard)

Sea level: 1,013.25 hPa
1,000 ft (305m): 977 hPa
5,000 ft (1,524m): 843 hPa
10,000 ft (3,048m): 697 hPa (cabin pressure)
18,000 ft (5,486m): 500 hPa (FL180)
Mount Everest (29,029 ft): ~313 hPa

Aviation Flight Levels

FL000 (sea level): 1,013 hPa
FL100 (10,000 ft): 697 hPa
FL180 (18,000 ft): 500 hPa
FL300 (30,000 ft): 301 hPa (cruise altitude)
FL390 (39,000 ft): 188 hPa (high cruise)

Geographic Variations

Dead Sea (-430m): ~1,063 hPa (lowest point on Earth)
Amsterdam (sea level): ~1,013 hPa
Denver (1,609m): ~835 hPa
Mexico City (2,240m): ~760 hPa
La Paz, Bolivia (3,640m): ~640 hPa

Hectopascal Conversion Formulas

To Pascal:

1 hPa = 100 Pa

Example: 5 hectopascals = 500 pascals

To Kilopascal:

1 hPa = 0.1 kPa

Example: 5 hectopascals = 0.5 kilopascals

To Megapascal:

1 hPa = 0.0001 MPa

Example: 5 hectopascals = 0.0005 megapascals

To Bar:

1 hPa = 0.001 bar

Example: 5 hectopascals = 0.005 bars

To Millibar:

1 hPa = 1 mbar

Example: 5 hectopascals = 5 millibars

To Atmosphere:

1 hPa = 0.000987 atm

Example: 5 hectopascals = 0.004935 atmospheres

To Technical Atmosphere:

1 hPa = 0.00102 at

Example: 5 hectopascals = 0.005099 technical atmospheres

To Torr:

1 hPa = 0.750062 Torr

Example: 5 hectopascals = 3.750308 torr

To Millimeter of Mercury:

1 hPa = 0.750062 mmHg

Example: 5 hectopascals = 3.750308 millimeters of mercury

To Inch of Mercury:

1 hPa = 0.02953 inHg

Example: 5 hectopascals = 0.14765 inches of mercury

To Pound per Square Inch:

1 hPa = 0.014504 psi

Example: 5 hectopascals = 0.072519 pounds per square inch

To Kilopound per Square Inch:

1 hPa = 0.000015 ksi

Example: 5 hectopascals = 0.000073 kilopounds per square inch

To Kilogram-force per Square Centimeter:

1 hPa = 0.00102 kgf/cm²

Example: 5 hectopascals = 0.005099 kilograms-force per square centimeter

To Kilogram-force per Square Meter:

1 hPa = 10.197162 kgf/m²

Example: 5 hectopascals = 50.985811 kilograms-force per square meter

To Millimeter of Water Column:

1 hPa = 10.197162 mmH₂O

Example: 5 hectopascals = 50.985811 millimeters of water column

To Inch of Water Column:

1 hPa = 0.401463 inH₂O

Example: 5 hectopascals = 2.007315 inches of water column

Frequently Asked Questions

Formula: PSI = hPa × 0.0145 Examples:

1,013 hPa = 14.7 PSI (sea level)
1,000 hPa = 14.5 PSI
900 hPa = 13.05 PSI
800 hPa = 11.6 PSI hPa to PSI converter →

Convert Hectopascal

Need to convert Hectopascal to other pressure units? Use our conversion tool.

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