Density to Specific Gravity

## Related Tools

## User Guide

This calculator will compare the substance density you have entered with the density of pure water and display the result as a specific gravity decimal ratio. A conversion scale showing SG values for a range of density values will also be displayed, which will change according to the entered density.

- Enter the density value to be converted in the upper input box.
- Select the corresponding mass and volumetric units from the upper pair of selection boxes to define the density measurement units.
- The density will be displayed as a specific gravity ratio in the lower text box.

### The difference between specific gravity and density

On the surface, their values are relatively close. In essence, they are indeed interrelated. The density of an object determines the specific gravity of an object, and the specific gravity of an object is a specific manifestation of the density of an object, also known as relative density.

The density of an object reflects the inherent characteristics of the object and is the mass of the object per unit volume. The mass of the object is certain.

The specific gravity of an object reflects the weight of an object per unit volume. The weight of an object is caused by gravity, and it will change.

Except for gas, the gravity of a certain volume of any substance, compared with the gravity of the same volume of water at 4°C, is called the specific gravity of the substance. The density of water is equal to 1 g/cm3 at 4°C. The gravity of a substance is proportional to its mass, and the gravity of its unit volume must be proportional to its density.

Therefore, the specific gravity of any substance is equal to the density of the substance and water at 4°C. Therefore, the specific gravity of a substance is often equal to the value of its density. Only the density must be in 1 g/cm3 as the unit, and the specific gravity is only a pure number, so the meaning is never the same.

In short, the specific gravity is the relative density of a unit volume of substance and the same unit of water. According to the 1978 International Pure Applied Physics

#### Formula

The conversion formula used by this tool is:

SG = ρ / ρ0

**Symbols**

- ρ = Density of substance in kgm-3
- ρ0 = Density of pure water (1000 kgm-3 @4°C)
- SG = Specific gravity (e.g. pure water = 1)

#### Density of Substance (ρ)

This is the measure of the amount of mass per unit volume of a substance. The density is derived by dividing the mass of a quantity of substance by its volume.

#### Specific Gravity of Substance (SG)

This is the ratio of the density of a substance compared to the density of pure water.