Convert Millibar to Pascal (mbar → Pa)

Converting millibars to pascals is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in millibars

   Start with the number of millibars (mbar) you want to convert.
2. 2
   Multiply by 100

   The conversion factor from mbar to Pa is 100. Multiply your value by this number.
3. 3
   Read the result in pascals

   The result is your value in pascals (Pa).

Multiply the value in millibars by 100. For the reverse direction, multiply by 0.01.

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

• ✗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.

What is the Millibar?

The millibar equals exactly 100 pascals and is the legacy meteorology unit, identical to the modern hectopascal (hPa). Most weather services worldwide transitioned from millibars to hectopascals in the late 20th century, but the unit persists in aviation weather reports, marine forecasts, and older barometric instruments. Standard sea-level atmospheric pressure is 1,013.25 mbar (or hPa). Hurricane and typhoon central pressures are reported in millibars: a major Category 5 hurricane like Hurricane Andrew (1992) had a central pressure of about 922 mbar. The millibar relates to the hectopascal (1 mbar = 1 hPa exactly), the bar (1,000 mbar = 1 bar), the pascal (100 Pa = 1 mbar), and the atmosphere (1,013.25 mbar = 1 atm). Despite the official preference for hPa, the millibar is retained in some traditional contexts and older texts.

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

What is the Pascal?

The pascal is the SI unit of pressure, equal to 1 newton per square meter (1 N/m²). Named after French mathematician and physicist Blaise Pascal (1623–1662), it became the SI standard in 1971. One pascal is a very small pressure: atmospheric pressure at sea level is about 101,325 Pa, the human breath exerts roughly 100 Pa above ambient, and tire pressure is in the hundreds of thousands of pascals. Because the pascal is small, the kilopascal (1 kPa = 1,000 Pa), megapascal (1 MPa = 10⁶ Pa), and gigapascal (1 GPa = 10⁹ Pa) are more commonly used in practice. Modern weather forecasts use hectopascals (1 hPa = 100 Pa = 1 millibar). The pascal relates to the bar (1 bar = 100,000 Pa), the psi (1 psi ≈ 6,895 Pa), the atmosphere (1 atm = 101,325 Pa), and mmHg (1 mmHg ≈ 133.3 Pa). Scientific and engineering publications use the pascal universally.

• Scientific and engineering calculations
• Ventilation and HVAC airflow pressures
• Acoustic pressure (sound) measurements