Transparent method
The formula
Worked example
Example inputs
How to interpret the result
Specific gravity is density expressed relative to water, which is what makes the number immediately meaningful without needing to remember water's own density in a specific unit system. Anything above 1 sinks in water, anything below 1 floats, a fast, intuitive read that raw density alone doesn't offer as directly.
Before you rely on it
What to check
Confirm mass and volume are measured in compatible units before dividing, since a units mismatch produces a density figure that looks plausible but is actually off by whatever factor the unit conversion was missing.
The common error
Where people go wrong with density calculator
Comparing raw density values measured in different unit systems without converting to a common basis first. Two genuinely different-looking density numbers can represent the identical material once the units are actually reconciled.
Sensitivity evidence
How mass (g) changes the density (g/cm³)
| Mass (g) | Density (g/cm³) | Specific gravity (relative to water) |
|---|---|---|
| 80 | 1.6 | 1.6 |
| 90 | 1.8 | 1.8 |
| 100worked example | 2 | 2 |
| 110 | 2.2 | 2.2 |
| 120 | 2.4 | 2.4 |
Every input, tested
Which input moves the density (g/cm³) most
| Input | Tested from | To | Density (g/cm³) at each end | Swing |
|---|---|---|---|---|
| Volume (cm³) | 45 | 55 | 2.2 to 1.8 | 0.404 (20%) |
| Mass (g) | 90 | 110 | 1.8 to 2.2 | 0.4 (20%) |
Two variables at once
Density (g/cm³) by mass (g) and volume (cm³)
| Mass (g) \ Volume (cm³) | 40 | 50 | 60 |
|---|---|---|---|
| 80 | 2 | 1.6 | 1.3 |
| 90 | 2.3 | 1.8 | 1.5 |
| 100 | 2.5 | 2 | 1.7 |
| 110 | 2.8 | 2.2 | 1.8 |
| 120 | 3 | 2.4 | 2 |
Step by step
The worked example, input by input
| Input | Value used |
|---|---|
| Mass (g) | 100 |
| Volume (cm³) | 50 |
| Density (g/cm³) | 2 |
| Specific gravity (relative to water) | 2 |
Where the inputs come from
Enter the mass in grams and the volume in cubic centimeters. Weigh the sample on a scale and measure volume by dimensions, by the water it displaces or from a label. One cubic centimeter equals one milliliter. Use the same system of units so that density comes out in grams per cubic centimeter. For irregular objects, submerge them in a graduated cylinder and read the change in level.
When the result stops applying
Density depends on temperature and pressure, especially for gases and liquids, and water is densest at about 4 degrees Celsius. Porous objects may absorb water and give a wrong displacement volume. Alloys and mixtures have densities between their components. Measurement errors in volume dominate for small samples.
What to compare it with
Convert mass and volume on the weight and volume converters, and compute volumes on the cylinder, sphere and rectangular prism calculators. The molarity and dilution pages use concentrations, and the percent error calculator measures how close your result is to a reference value.
People also ask
Frequently asked questions
What is specific gravity?
The ratio of a substance's density to the density of water, so a value above 1 sinks and below 1 floats in water.
How do I measure the volume of an irregular object?
Submerge it in water and measure how much the water level rises, which equals the object's volume.
Why does density change with temperature?
Most materials expand when heated, so the same mass occupies more volume and the density falls as the temperature rises.