Convert Millimeter of Mercury to Pascal (mmHg → Pa)

Converting millimeters of mercury 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 millimeters of mercury

   Start with the number of millimeters of mercury (mmHg) you want to convert.
2. 2
   Multiply by 133.32239

   The conversion factor from mmHg to Pa is 133.32239. 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 millimeters of mercury by 133.32239. For the reverse direction, multiply by 0.007501.

• ✓1 mmHg ≈ 133.32 Pa ≈ 1 Torr.
• ✓760 mmHg = 1 atm.
• ✓Blood-pressure cuffs display mmHg worldwide.

• ✗Confusing mmHg with mmH₂O (different unit, factor of 13.6).
• ✗Mixing mmHg with torr in precise vacuum physics — they differ by one part per million.
• ✗Writing blood pressure in kPa — use mmHg for medical continuity.

What is the Millimeter of Mercury?

The millimeter of mercury equals approximately 133.322 pascals and is the universal medical unit for blood pressure measurements worldwide. Normal blood pressure is around 120/80 mmHg (systolic/diastolic). The unit's origin is the manometer: a column of mercury rises 1 mm for every 133 Pa of pressure difference. Mercury barometers historically measured atmospheric pressure (760 mmHg = 1 atm at sea level). Beyond medicine, mmHg appears in vacuum-system specifications, certain laboratory contexts, and altimeter settings (in inHg in the US, in mmHg or hPa elsewhere). The mmHg relates to the torr (1 mmHg ≈ 1.0000003 torr — essentially identical), the pascal (1 mmHg ≈ 133.3 Pa), the atmosphere (760 mmHg = 1 atm), and inches of mercury (1 inHg = 25.4 mmHg). The unit's persistence in medicine reflects historical inertia and the precision of mercury manometers.

• Blood pressure measurement globally
• Vacuum-system specifications
• Historical scientific texts

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