Water Density Calculator

Water Density Calculator - Calculate water density from temperature, salinity, and pressure

Water Density (kg/m³):

Water Density (kg/dm³):

Water Density (kg/L):

Water Density (g/L):

Water Density (g/mL):

Water Density (g/cm³):

Water Density (oz/cu in):

Water Density (lb/cu in):

Water Density (lb/cu ft):

Water Density (lb/cu yd):

Water Density (lb/US gal):

Water Density (mg/L):

What is Water Density

Water density is the mass per unit volume of water, typically measured in kg/m³. It varies with temperature, salinity, and pressure. The density of pure water at 1 bar is calculated using a polynomial function of temperature, while salinity and pressure adjustments account for dissolved salts and compression, respectively. This calculator estimates water density based on these factors.

For example, at 100 °C, 25 ‰ salinity, and 2,222 bar, the density is 1,058.63 kg/m³.

How to Calculate Water Density

Water Density Calculation: The density is calculated in three steps:

Temperature Effect: Base density of pure water at 1 bar is given by: \[ \rho(T) = \rho_0 + (a_1 \times T) - (a_2 \times T^2) + (a_3 \times T^3) - (a_4 \times T^4) + (a_5 \times T^5) \] where \(\rho_0 = 999.83311 \, \text{kg/m³}\), \(a_1 = 0.0752\), \(a_2 = 0.0089\), \(a_3 = 7.36413 \times 10^{-5}\), \(a_4 = 4.74639 \times 10^{-7}\), and \(a_5 = 1.34888 \times 10^{-9}\), with \(T\) in °C.
Salinity Effect: Add \(0.8 \cdot S \, \text{kg/m³}\), where \(S\) is salinity in ‰.
Pressure Effect: Multiply by a compression factor \((1 + \beta \cdot (P - 1))\), where \(\beta \approx 4.6 \times 10^{-5} \, \text{per bar}\) and \(P\) is pressure in bar.

Use the form above to input your temperature, salinity, and pressure values, and the calculator will compute the water density in multiple units.

Density Units and Conversions

The calculator displays water density in the following units:

Kilogram per cubic meter (kg/m³): Base unit
Kilogram per cubic decimeter (kg/dm³): 1 kg/dm³ = 1000 kg/m³
Kilogram per liter (kg/L): 1 kg/L = 1000 kg/m³
Gram per liter (g/L): 1 g/L = 1 kg/m³
Gram per milliliter (g/mL): 1 g/mL = 1000 kg/m³
Gram per cubic centimeter (g/cm³): 1 g/cm³ = 1000 kg/m³
Ounce per cubic inch (oz/cu in): 1 kg/m³ = 0.000578036 oz/in³
Pound per cubic inch (lb/cu in): 1 kg/m³ = 0.0000361273 lb/in³
Pound per cubic foot (lb/cu ft): 1 kg/m³ = 0.0624279 lb/ft³
Pound per cubic yard (lb/cu yd): 1 kg/m³ = 1.68555 lb/yd³
Pound per US gallon (lb/US gal): 1 kg/m³ = 0.0083454 lb/US gal
Milligram per liter (mg/L): 1 kg/m³ = 1000 mg/L

Pressure Units and Conversions

The calculator accepts pressure in the following units:

Pascals (Pa): 1 bar = 100000 Pa
Bars (bar): Base unit for calculation
Pounds per square inch (psi): 1 psi ≈ 0.0689476 bar
Technical atmospheres (at): 1 at ≈ 0.980665 bar
Standard atmospheres (atm): 1 atm ≈ 1.01325 bar
Torr (Torr): 1 bar ≈ 750.062 Torr
Hectopascals (hPa): 1 hPa = 0.001 bar
Kilopascals (kPa): 1 kPa = 0.01 bar
Megapascals (MPa): 1 MPa = 10 bar
Gigapascals (GPa): 1 GPa = 10000 bar
Inches of mercury (inHg): 1 inHg ≈ 0.0338639 bar
Millimeters of mercury (mmHg): 1 mmHg ≈ 0.00133322 bar

Standard Water Densities

Water density varies with conditions. Some standard values include:

Pure water at 0 °C, 1 bar: \(\rho \approx 999.83 \, \text{kg/m³}\)
Pure water at 20 °C, 1 bar: \(\rho \approx 998.20 \, \text{kg/m³}\)
Pure water at 100 °C, 1 bar: \(\rho \approx 958.38 \, \text{kg/m³}\)
Seawater (35 ‰) at 20 °C, 1 bar: \(\rho \approx 1025 \, \text{kg/m³}\)

Use this calculator to estimate density for different conditions.

What is Salinity?

Salinity is the concentration of dissolved salts in water, typically measured in parts per thousand (‰). It affects water density, with higher salinity increasing density due to the added mass of salts.

FAQs

How do you calculate water density?

To calculate water density:

Determine the base density of pure water at 1 bar using the polynomial formula.
Adjust for salinity by adding a salinity term.
Adjust for pressure using the compressibility of water.

What is the density of water at 100 °C, 25 ‰, and 2,222 bar?

The density is 1,058.63 kg/m³, as shown in the image.