Density Calculator
Calculate density from mass and volume.
Try an example
5,000 kg/m³
About this calculator
How This Density Calculator Works
Enter a mass and a volume, and the calculator returns the density — how much mass is packed into a given amount of space.
Worked Example
An object with a mass of 10 kg and a volume of 0.002 m³ has a density of 5,000 kg/m³ (5 g/cm³) — denser than water, so it would sink.
The Formula
Density = Mass ÷ Volume. The result is shown in both kg/m³ (the standard SI unit, common in engineering) and g/cm³ (more commonly used for everyday materials — water is exactly 1 g/cm³ at standard conditions).
Why Density Determines Whether Something Floats
An object floats in a fluid when its density is lower than the fluid's density, and sinks when it's higher — this is the basis of buoyancy. Water has a density of about 1,000 kg/m³, so a material lighter than that (like most wood, ice, or an air-filled hull) floats, while denser materials (most metals, dense rock) sink, regardless of the object's total size or weight alone.
Worked example
An object with a mass of 10 kg and a volume of 0.002 m³ has a density of 5,000 kg/m³ (5 g/cm³) — denser than water, so it would sink.
Frequently asked questions
How does density determine whether something floats?
An object floats in a fluid if its density is less than the fluid's density — water has a density of about 1,000 kg/m³ (1 g/cm³), so anything less dense than that floats, and anything denser sinks.
Why do the two units (kg/m³ and g/cm³) matter?
They're just different scales for the same measurement — g/cm³ is more commonly used for everyday materials (water is exactly 1 g/cm³), while kg/m³ is the standard SI unit used in most engineering and scientific contexts.