The Specific Gravity calculator computes the Specific Gravity (SG) based on the ratio of the specific weight of a substance to the specific weight of water under standard conditions.
Standard temperature and pressure (STP) is defined as `0^@`C and 100kPa pressure. And the specific weight of water is 9789.030391945 kg/(m²·s²). Note the specific gravity of water can vary as a function of temperature and pressure.