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Density of Mercury at 20 °C

ρHg=13,546 kg/m3\rho_{\mathrm{Hg}} = 13,546\ \text{kg/m}^{3}
Value13.546 g/cm³ (13,546 kg/m³)
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StatusMeasured: ± 0.003 g/cm³ (2.2 × 10⁻⁴ relative)
SourceNational Standards Commission (Australia), Determination of the Recognized-Value Standard of Measurement of Density of Mercury, 1985: 13 545.87 kg/m³ at 20 °C (13 533.6 at 25 °C)
CategoriesMaterial PropertiesEngineering & TradeFluid Properties
Density of Mercury at 20 °C in every density unit
UnitValue
gram per cubic centimeter13.546 g/cm³
kilogram per cubic meter13,546 kg/m³
pound per cubic foot845.64915 lb/ft³
kilogram per liter13.546 kg/L
pound per cubic yard22,832.527 lb/yd³
gram per liter13,546 g/L
pound per imperial gallon135.7636 lb/imp gal
pound per US gallon113.04685 lb/gal
8 more density units
microgram per liter13,546,000,000 μg/L
milligram per cubic meter13,546,000,000 mg/m³
milligram per liter13,546,000 mg/L
slug per cubic foot26.283579 slug/ft³
gram per milliliter13.546 g/mL
tonne per cubic meter13.546 t/m³
US short ton per cubic yard11.416264 ton/yd³
pound per cubic inch0.4893803 lb/in³

Learning zone

Mercury's density is why barometers are 760 mm tall instead of ten metres. The conventional millimetre of mercury is defined with mercury at 0 °C, where its density is 13 595.1 kg/m³, under standard gravity: 1 mmHg = 133.322 Pa exactly by that definition. At 20 °C the liquid is 0.36 % less dense, so a mercury column read at 20 °C and not temperature-corrected reads high by about 2.8 mmHg at atmospheric pressure: a real error in blood-pressure and vacuum work, and the reason lab manometers come with correction tables.

Use it as a reference and a teaching value rather than a working fluid. Mercury manometers have largely been replaced by transducers on toxicity grounds, but the unit survives in medicine (mmHg), vacuum practice (torr, within one part in seven million of a mmHg) and North American barometry (inHg). The 13.6 ratio to water is worth memorising: one inch of mercury is 13.6 inches of water column, and 29.92 inHg is one atmosphere.

Used by 4 solvers

Density

ρ=mV\rho = \tfrac{m}{V}

Hydrostatic Pressure (P = ρgh)

P=ρghP = \rho g h

Pressure Head (h = P/ρg)

h=Pρgh = \frac{P}{\rho g}

Specific Gravity

SG=ρρwaterSG = \frac{\rho}{\rho_{water}}
Revised 31 October 2026
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formula.expert. (2026, October 31). Density of Mercury at 20 °C. https://formula.expert/constants/density-mercury