Density Calculator
Free density calculator — solve density, mass, or volume from the other two, with unit conversions and a float-or-sink check.
Everyday Uses
Material identification
Mass plus displaced volume identifies an unknown metal — the Archimedes method, computed.
Float-or-sink predictions
The built-in water comparison answers the classic question before you drop it in.
Weight estimation
Density times volume predicts what a part or pour will weigh before you make it.
Chemistry class
Solve any of ρ, m, V from the other two with unit conversions handled.
Frequently Asked Questions
What is density and how is it calculated?
Density is mass per unit volume: ρ = m/V. A 250 g object occupying 100 cm³ has a density of 2.5 g/cm³. It's an intrinsic property — a gold coin and a gold bar have the same density — which makes it useful for identifying materials and predicting buoyancy.
How do g/cm³, kg/m³, and lb/ft³ relate?
1 g/cm³ = 1,000 kg/m³ = 62.43 lb/ft³. Water is the anchor point: 1 g/cm³ exactly (at 4°C). Science tables usually quote kg/m³, engineering handbooks lb/ft³, and chemistry g/cm³ — this calculator converts between all three automatically.
Why do things float or sink?
An object floats if its overall density is below the fluid's. Ice (0.917 g/cm³) floats on water; steel (7.85) sinks — yet steel ships float because their overall density, hull air included, is below 1. The float-or-sink indicator here compares your result against water.
Can density identify an unknown material?
It's a strong first clue. Measure mass with a scale and volume by water displacement, then compare: aluminum ≈ 2.7, iron/steel ≈ 7.8, copper ≈ 8.96, silver 10.5, lead 11.34, gold 19.32 g/cm³. Archimedes reportedly exposed a fake gold crown exactly this way — dense metals are hard to counterfeit.