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What is a millibar?

The meteorology pressure unit — 100 pascals

Definition

The millibar equals 100 pascals or 1/1000 bar. It is the traditional unit for atmospheric pressure in meteorology (now called hectopascal, hPa, but numerically identical). Sea-level pressure averages 1013 mbar.

Common uses

  • Weather reports and atmospheric pressure
  • Altimetry and aviation
  • Historical weather records

🌍 Real-world scale

Sea-level average: 1013 mbar. Deep low-pressure storm: below 980 mbar. Hurricane eye: below 920 mbar.

Convert from millibars

9 conversions
Millibar to Pascal1 mbar = 100 PaMillibar to Kilopascal1 mbar = 0.1 kPaMillibar to Megapascal1 mbar = 0.0001 MPaMillibar to Bar1 mbar = 0.001 barMillibar to Pound per Square Inch1 mbar = 0.0145 psiMillibar to Atmosphere1 mbar = 0.0009869 atmMillibar to Millimeter of Mercury1 mbar = 0.7501 mmHgMillibar to Torr1 mbar = 0.7501 TorrMillibar to Inch of Mercury1 mbar = 0.02953 inHg

Convert to millibars

9 conversions
Pascal to Millibar1 Pa = 0.01 mbarKilopascal to Millibar1 kPa = 10 mbarMegapascal to Millibar1 MPa = 10,000 mbarBar to Millibar1 bar = 1,000 mbarPound per Square Inch to Millibar1 psi = 68.9476 mbarAtmosphere to Millibar1 atm = 1,013.25 mbarMillimeter of Mercury to Millibar1 mmHg = 1.33322 mbarTorr to Millibar1 Torr = 1.33322 mbarInch of Mercury to Millibar1 inHg = 33.8639 mbar

Tips

  • 1 mbar = 1 hPa = 100 Pa.
  • Weather reports: "1013 hPa" and "1013 mbar" mean the same thing.
  • Hurricane strength correlates with central pressure drop.

Common mistakes

  • Confusing mbar and bar — 1000× difference.
  • Using mbar for industrial pressures — too small.
  • Mixing hPa and mbar in casual writing without noting they are equal.

FAQ about the millibar

What is a millibar?
The millibar equals 100 pascals or 1/1000 bar. It is the traditional unit for atmospheric pressure in meteorology (now called hectopascal, hPa, but numerically identical). Sea-level pressure averages 1013 mbar.
Where is the millibar used?
The millibar is commonly used for: Weather reports and atmospheric pressure; Altimetry and aviation; Historical weather records.
What is an example of a millibar in real life?
Sea-level average: 1013 mbar. Deep low-pressure storm: below 980 mbar. Hurricane eye: below 920 mbar.
What category does the millibar belong to?
The millibar is a unit of pressure, part of the 10-unit pressure category on UnitConv.
How accurate are millibar conversions?
All conversion factors follow NIST and BIPM international standards to 8 significant figures — the highest practical accuracy.
Explore all 10 pressure units and their conversions.🎈 Pressure hub →