Density of Mercury at 20 °C

\rho_{\mathrm{Hg}} = 13,534\ \text{kg/m}^{3}

Value	13,534 kg/m³
Status	Measured: ± 3 kg/m³ (0.00022 relative)
Source	CRC Handbook of Chemistry and Physics, 104th ed.
Categories	Material Properties Engineering & Trade fluids

ρ_Hg in every density unit

kilogram per cubic meter	13,534 kg/m³
gram per cubic centimeter	13.534 g/cm³
gram per milliliter	13.534 g/mL
kilogram per liter	13.534 kg/L
pound per cubic foot	844.90002 lb/ft³
pound per US gallon	112.9467 lb/gal

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 room temperature the liquid is 0.45 % less dense, so a mercury column read at 20 °C and not temperature-corrected reads high by about 3.4 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 Mercury manometers have largely been replaced by transducers on toxicity grounds, but the unit survives in medicine (mmHg), vacuum practice (torr, within one part in seven million of a mmHg) and North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 these solvers

Density

\rho = \tfrac{m}{V}

Specific Gravity

SG = \frac{\rho}{\rho_{water}}

Hydrostatic Pressure (P = ρgh)

P = \rho g h

Pressure Head (h = P/ρg)

h = \frac{P}{\rho g}