Density is the ratio of the mass to the volume of a substance: ρ = m/V [1] where V = volume, units typically [cm3] or [ft3] Pure water has its highest density 1000 kg/m3 or 1.940 slug/ft3 at temperature 4°C (=39.2°F). Specific weight is the ratio of the weight to the volume of a substance: γ = (m * g)/V = ρ * g [2] where g = acceleration due to gravity, units typically [m/s2] and value on Earth usually given as 9.80665 m/s2 or 32.17405 ft/s2 V = volume, units typically [cm3] or [ft3] ρ = density, units typically [g/cm3] or [lb/ft3] Example 1: Specific weight of water γ = 1000 [kg/m3] * 9.807 [m/s2] = 9807 [kg/(m2 s2)] = 9807 [N/m3] = 9.807 [kN/m3] In the Imperial system the mass unit is the slug [sl], and is derived from the pound-force by defining it as the mass that will accelerate at 1 foot per square second when a 1 pound-force acts upon it: 1 [lbf] = 1 [sl] * 1 [ft/s2] and 1 [sl] = 1 [lbf]/1 [ft/s2] The density of water is 1.940 sl/ft3 at 39 °F (4 °C), and the specific weight in Imperial units is γ = 1.940 [sl/ft3] * 32.174 [ft/s2] = 1.940 [lbf]/([ft/s2]*[ft3]) * 32.174 [ft/s2] = 62.4 [lbf/ft3] See more about the difference between mass and weight Online Water density CalculatorThe calculator below can be used to calculate the liquid water density at given temperatures. Note! Temperature must be within the ranges 0-370 °C, 32-700 °F, 273-645 K and 492-1160 °R to get valid values.
The density of water depends on temperature and pressure as shown below: See Water and Heavy Water for thermodynamic properties at standard condtions. As shown in the figures, the change in density is not linear with temperature - this means that the volumetric expansion coefficient for water is not constant over the temperature range. Water density, specific weight and thermal expansion coefficient at temperatures given in degree Celcius: For full table with Specific Weight and Thermal Expansion Coefficient - rotate the screen!
For full table with Specific Weight and Thermal Expansion Coefficient - rotate the screen!
Water density and specific weight at 1000 psi and given temperatures: For full table with Specific Weight - rotate the screen!
For full table with Specific Weight - rotate the screen!
Weight per US gallon is based on 7.48 gallons per cubic foot.
To convert from density in kg/m3 to other density units - or between units - use the converting values below:
See also Example 2: Water Density in unit oz/in3 998.21 [kg/m3] * 0.0005780 [(oz/in3)/(kg/m3)] = 0.5797 [oz/in3] Example 3: Mass of Hot Water A tank with volume 10 m3 contains hot water with temperature 190°F. From the table above the density of water at 190°F is 966.8 kg/m3. The total mass of the water in the tank can be calculated 10 [m3] * 966.8 [kg/m3] = 9668 [kg] See also hydrostatic pressure in water and energy stored in hot water |