Created By : Naaz Fatima

Reviewed By : Rajashekhar Valipishetty

Last Updated : Apr 10, 2023

Water Density Calculator finds the density of the salt water easily and you can also know will the object float or sink in the salt water. This tool determines the salt water density by taking the temperature, salinity and pressure details.

Step by Step Process to Calculate Salt Water Density

Below provided are the simple steps you need to check while finding the salt water density. Get an idea and follow these steps to get the output effortlessly.

  • Get the temperature, salinity of water and pressure from the question.
  • Check the formula to calcyukate the density of sea water.
  • Substitute the values in the formula.
  • Solve the equation to obtain the water density value.

What is Density of Salt Water?

The density of any substance is defined as the ratio of substance mass to its volume. The symbol to represent density is ρ. The units of density of water are kg/m3, lb/ft3, g/ml or g//cm3.

The formula to calculate density is ρ = mass of the substance/volume of the substance

The density of water depends on the temperature and pressure. The change in density with the change of temperature is caused due to thermal expansion which states that the quantity of space occupied by a substance increases as the temperature increases. So, the water mass remains constant, but the increase in volume causing the increase in density.

Because of the intriguing property of water, it reaches maximum density at 4°C. The equation to get the temperatures is

ρ(T) = ρo + a1T + a2T2 + a3T3 + a4T4 + a5T5

The values of the coefficients are ρΓéÇ = 999.83311 kg/m³, aΓéü = 0.0752 kg/(m³·°C), aΓéé = -0.0089 kg/(m³·°C²), aΓéâ = 7.36413*10Γü╗Γü╡ kg/(m³·°C³), aΓéä = 4.74639*10Γü╗Γü╖ kg/(m³·°CΓü┤), and aΓéà = 1.34888*10Γü╗Γü╣ kg/(m³·°CΓü╡)

Salinity: The amount of salt present in the salt water is called the salinity. The units are ppt, psu, or per mile ‰

Salinity formula is S = m1/(m + mo)


mo is the pure water mass

m1 is the salt water mass.

Salt Water Density

Salt water density depends on the temperature, salinity and pressure of the water. Its formula is

ρ(T,S,p) = ρ(T) + f(T,S,p)

Where ρ(T) is the pure water density.


The density of salt water increases with higher salinity, more external pressure.



Question: What is the densiy of water at 25°C of salinity S = 32 ‰ and under the pressure of 1 atm?


Given that

Temperature T = 25°C

Salinity S = 32 ‰

Pressure = 1 atm

By using the Water Density Calculator, the density of water is 1,021.2 kg/m3

Physicscalc.Com has got concepts like friction, acceleration due to gravity, water pressure, gravity, and many more along with their relevant calculators all one under one roof.

Frequently Asked Questions on Water Density Calculator

1. How to use the Water Density Calculator?

You have to enter the temperature, the salinity of sea water and pressure in the specified input fields of the Density of Sea Water Calculator. Press the calculate button to get the density as output within no time.

2. Which instrument measure the water density?

A hydrometer is an instrument that is used to measure the density of water.

3. How Salinity is measured?

Salinity is nothing but the amount of salt in sea water. The mixing of mass of pure water and mass of salt is the salinity of salt water. The formula is S = m1/(m + mo)

4. Should Egg float or sink in the sea water?

The egg sinks or floats in the sea water depends on the fresh or rotten egg and on the salinity of the water. As the mass decreases and the volume of the egg remains constant means density decreases.

5. What is the sound speed in water?

The formula to calculate the speed of sound in air is c = √(γ * p / ρ). Where γ is the adiabatic index, p is the pressure, and ρ is the air density. The speed of sound in water increases when the density decreases over a wide range of temperatures.