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hPa to mmHg Converter
Convert Hectopascals to Millimeters of Mercury. Features gravity correction for high-precision clinical and meteorological applications. Clean, distraction-free interface.
About
In medical diagnostics and laboratory physics, precise pressure readings are vital. While the Hectopascal (hPa) is standard for weather, the Millimeter of Mercury (mmHg) remains the gold standard for blood pressure measurement (sphygmomanometry) and vacuum systems. The discrepancy between these units can lead to confusion when comparing environmental data with physiological or experimental constraints.
This tool offers a specialized conversion environment that accounts for the nuances of mercury manometry. Unlike basic calculators, it acknowledges the role of gravity. The definition of mmHg relies on the density of mercury and the acceleration of gravity. For general use, standard gravity is assumed, but this tool provides a toggle for "Local Gravity" correction - a critical feature for laboratories operating at high altitudes or specific latitudes where standard constants introduce systematic error.
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medical converter
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hPa
mmHg
Torr
Formulas
The conversion is based on the hydrostatic pressure formula:
P = ρ ⋅ g ⋅ h
Where:
- ρ (Density of Hg) ≈ 13595.1 kg/m3
- g (Standard Gravity) = 9.80665 m/s2
Under standard conditions, the conversion factor is:
1 hPa ≈ 0.75006156 mmHg
Reference Data
| Input (hPa) | Output (mmHg) | Significance |
|---|---|---|
| 950 | 712.56 | Typical Eye of Hurricane |
| 1000 | 750.06 | Borderline Low Pressure |
| 1013.25 | 760.00 | Standard Atmosphere (1 atm) |
| 1020 | 765.06 | High Pressure Zone |
| 1050 | 787.56 | Extreme High Pressure |
| 120 / 80 * | 90 / 60 | (*Reverse Comparison for BP) |
Frequently Asked Questions
Millimeters of Mercury is a "manometric" unit. It represents the height of a liquid column. The weight of that liquid depends on gravity. If gravity is lower (e.g., on a mountain), the same atmospheric pressure will support a higher column of mercury, changing the reading.
They are effectively identical for most practical purposes (within 0.000015%). Torr is defined as exactly 1/760th of a standard atmosphere, while mmHg is defined by the density of mercury.
It is suitable for educational and reference purposes. Clinical device calibration should strictly adhere to the manufacturer"s ISO manuals.