Calculator
Use direct density, mass-volume, or immersion inputs. Results appear above this form after submission.
Formula Used
Relative Density = ρsample / ρreference
Density = Mass / Volume
Relative Density = (Mass / Volume) / ρreference
Relative Density = Wair / (Wair − Wfluid)
Relative density is dimensionless. It compares a material density to a chosen reference density. When water is the reference, relative density and specific gravity are numerically equal.
How to Use This Calculator
- Select the calculation method that matches your available data.
- Choose a preset reference or enter a custom reference density.
- Enter sample density, mass and volume, or immersion values.
- Pick the correct units for every field.
- Choose your preferred decimal precision.
- Click the calculate button.
- Review the result card, interpretation, and Plotly graph.
- Use CSV or PDF export to save the result.
Example Data Table
| Material | Sample Density (kg/m³) | Reference | Reference Density (kg/m³) | Relative Density | Interpretation |
|---|---|---|---|---|---|
| Aluminum | 2700 | Water | 1000 | 2.7000 | Denser than water |
| Gasoline | 740 | Water | 1000 | 0.7400 | Less dense than water |
| Seawater Sample | 1025 | Water | 1000 | 1.0250 | Slightly denser than water |
| Carbon Dioxide | 1.98 | Air | 1.225 | 1.6163 | Denser than air |
| Oak Wood | 750 | Water | 1000 | 0.7500 | Likely floats in water |
FAQs
1. What is relative density?
Relative density is the ratio of a material’s density to a reference density. It has no unit because one density is divided by another density.
2. Is relative density the same as specific gravity?
Yes, in many engineering contexts they are used interchangeably, especially when water is the reference. Both express density comparison without units.
3. Why does the reference density matter?
The selected reference changes the ratio. Water is common for solids and liquids, while air is often used for gases and vapor comparisons.
4. What does a value greater than one mean?
A value above one means the sample is denser than the chosen reference. Against water, that usually means the material tends to sink.
5. Can I use mass and volume instead of density?
Yes. The calculator first computes density from mass divided by volume, then compares that density with the selected reference value.
6. When should I use the immersion method?
Use it when you know the object’s weight in air and its apparent weight in an immersion fluid. It is useful for solids and lab tests.
7. Does temperature affect relative density?
Yes. Density changes with temperature, especially for liquids and gases. For high accuracy, use densities measured at the same temperature conditions.
8. Why does the calculator show density and unit weight too?
These supporting values help engineers interpret the ratio more clearly. They also make reporting, design checks, and material comparison easier.