Density of Mercury at 20 °C
| Value | 13,534 kg/m³ |
| Status | Measured: ± 3 kg/m³ (0.00022 relative) |
| Source | CRC Handbook of Chemistry and Physics, 104th ed. |
| Categories | Material PropertiesEngineering & TradeFluid Properties |
| microgram per liter | 13,534,000,000 μg/L |
| milligram per cubic meter | 13,534,000,000 mg/m³ |
| milligram per liter | 13,534,000 mg/L |
| pound per cubic yard | 22,812.3 lb/yd³ |
| kilogram per cubic meter | 13,534 kg/m³ |
| gram per liter | 13,534 g/L |
| pound per cubic foot | 844.90002 lb/ft³ |
| pound per imperial gallon | 135.64334 lb/imp gal |
| pound per US gallon | 112.9467 lb/gal |
| slug per cubic foot | 26.260295 slug/ft³ |
| gram per cubic centimeter | 13.534 g/cm³ |
| gram per milliliter | 13.534 g/mL |
| kilogram per liter | 13.534 kg/L |
| tonne per cubic meter | 13.534 t/m³ |
| US short ton per cubic yard | 11.40615 ton/yd³ |
| pound per cubic inch | 0.48894677 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 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 Mercury manometers have largely been replaced by transducers on toxicity grounds, but the unit survives in medicine (mmHg), vacuum practice (torr, within one part in seven million of a mmHg) and North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.