Convert Millimeter of Mercury to Kilopascal (mmHg → kPa)

Converting millimeters of mercury to kilopascals 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 0.133322

   The conversion factor from mmHg to kPa is 0.133322. Multiply your value by this number.
3. 3
   Read the result in kilopascals

   The result is your value in kilopascals (kPa).

Multiply the value in millimeters of mercury by 0.133322. For the reverse direction, multiply by 7.500616.

• ✓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 Kilopascal?

The kilopascal equals 1,000 pascals and is the standard everyday pressure unit on tire labels (in metric countries), weather forecasts (often expressed as hPa or hectopascals, where 100 kPa = 1 atmosphere), and modern engineering documents. Car tire pressures are typically 200–250 kPa (29–36 psi), medical blood-pressure cuffs measure in mmHg but research increasingly uses kPa, and industrial process pressures are routinely given in kPa. The kilopascal is the most-used pressure unit in metric engineering practice, replacing the older 'kg/cm²' (kilogram-force per square centimeter, ≈ 98 kPa). It relates to the pascal (1,000 Pa = 1 kPa), the megapascal (1,000 kPa = 1 MPa), the bar (1 bar = 100 kPa), the psi (1 psi ≈ 6.895 kPa), and the atmosphere (1 atm ≈ 101.325 kPa). European tire pressure labels universally use kPa or bar.

• Tyre pressures in Canada, Australia
• Engineering pressure specs
• Weather pressure in some contexts