What is specific gravity?

Specific gravity is the ratio of a substance's density to a reference density. It is dimensionless and indicates whether a substance will float or sink in the reference material. For liquids and solids, the reference is usually water at 4°C (1000 kg/m³).

How do I use this calculator?

Enter the sample density in kg/m³ and the reference density in kg/m³. The calculator divides the sample density by the reference density to give the specific gravity. Ensure both densities are in the same units (kg/m³) for accurate results.

What does a specific gravity greater than 1 mean?

If the specific gravity is greater than 1, the sample is denser than the reference and will sink in it. If less than 1, it is less dense and will float. A value of 1 means equal densities.

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Specific Gravity Calculator.

Calculate specific gravity from sample and reference densities.

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Sample density

Reference density

Specific gravity

0,785

Results update automatically as you type.

Use Cases

Material Identification

Compare the density of an unknown material to a known reference to help identify it or verify its purity.

Example: A sample density of 2700 kg/m³ with water reference gives SG 2.7, typical for aluminum.

Quality Control in Manufacturing

Ensure consistency in products by checking that specific gravity falls within expected ranges, indicating proper composition.

Example: Checking a plastic batch with SG 0.92 against water reference to confirm it's polypropylene.

Frequently Asked Questions

What is specific gravity?: Specific gravity is the ratio of a substance's density to a reference density. It is dimensionless and indicates whether a substance will float or sink in the reference material. For liquids and solids, the reference is usually water at 4°C (1000 kg/m³).
How do I use this calculator?: Enter the sample density in kg/m³ and the reference density in kg/m³. The calculator divides the sample density by the reference density to give the specific gravity. Ensure both densities are in the same units (kg/m³) for accurate results.
What does a specific gravity greater than 1 mean?: If the specific gravity is greater than 1, the sample is denser than the reference and will sink in it. If less than 1, it is less dense and will float. A value of 1 means equal densities.

Tips & Common Mistakes

Tips

Always use the same units for both densities; the calculator expects kg/m³.
For most solids and liquids, use water at 4°C (1000 kg/m³) as the reference density.
Specific gravity is temperature-dependent; note the temperature of your measurements for precise work.
If you know the specific gravity and one density, you can rearrange the formula to find the other.

Common Mistakes to Avoid

Using different units for sample and reference densities, leading to incorrect ratios.
Forgetting that specific gravity is dimensionless and not a density itself.
Assuming the reference density is always water; it can be any fluid depending on the application.

Last updated: August 13, 2026