Inch of mercury

<p>Inch of mercury (inHg and ″Hg) is a non-<a href="/facts/SI/NShmfzlD">SI</a> <a href="/facts/Unit_of_measurement/pvTpWbmC">unit of measurement</a> for <a href="/facts/Pressure/eyc37GRG">pressure</a>. It is used for <a href="/facts/Barometric_pressure/wJLMSaVG">barometric pressure</a> in <a href="/facts/Weather_forecasting/nzqyMFCa">weather reports</a>, <a href="/facts/Refrigeration/Bs8HHbYd">refrigeration</a> and <a href="/facts/Aviation/HX5MHY71">aviation</a> in the <a href="/facts/United_States_customary_units/s76n3Bx4">United States</a>.
</p><p>It is the pressure exerted by a column of <a href="/facts/Mercury_(element)/WlxfoHva">mercury</a> 1 inch (25.4 mm) in height at the <a href="/facts/Standard_gravity/4L5M6jfQ">standard acceleration of gravity</a>.  Conversion to metric units depends on the density of mercury, and hence its temperature; typical conversion factors are:
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<table><tbody><tr><th>Conditions</th><th>Pressure</th></tr><tr><td>conventional</td><td>3386.389 pascals</td></tr><tr><td>32 °F (0 °C)</td><td>3386.38 pascals</td></tr><tr><td>60 °F (16 °C)</td><td>3376.85 pascals</td></tr></tbody></table>
<p>In older literature, an "inch of mercury" is based on the height of a column of mercury at 60 °F (15.6 °C).
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1 inHg60 °F = 3,376.85 pascals (33.7685 hPa)
<p>In Imperial units: 1 inHg60 °F = 0.489 771 <a href="/facts/Pounds_per_square_inch/RMdeTlB0">psi</a>, or 2.041 771 inHg60 °F = 1 psi.
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Inch of mercury open-in-new

Inch of mercury