Chemistry & Lab tools

Specific gravity calculator

Weigh a known volume, and see instantly whether it’s heavier or lighter than water — and by exactly how much.

Formula

Density = Mass ÷ Volume
Specific Gravity = Density ÷ Reference Density

Sample

Sample mass

Weight of the sample alone

Sample volume

Volume the sample occupies

Reference density

1.000 g/mL for water at 4°C

g/mL

Specific gravity

Density–

Relative to water–

Density vs. reference

Temperature affects density, so specific gravity readings should note the temperature they were taken at for anything requiring precision — most reference tables assume 20–25°C for the sample and 4°C for water. For quick QC checks, comparing against a known-good reading at the same temperature is usually good enough.

Frequently asked questions

What is specific gravity?

The ratio of a substance’s density to the density of a reference substance, usually water at 4°C, which has a density of exactly 1 g/mL.

How do I measure the density of a liquid?

Weigh an empty container, fill it with a known volume, weigh again, and divide the mass of liquid alone by the volume to get density in g/mL.

What does SG above or below 1 mean?

Above 1 means denser than water and it will sink; below 1 means less dense than water and it will float.

Is this specific gravity calculator free to use?

Yes. It runs entirely in your browser, needs no account, and nothing you enter is stored or transmitted.