Density Calculator
Enter a mass and a volume and get the density in kg/m³ — the single number that tells you how tightly matter is packed and whether something floats.
Mass and volume in, density out
Enter the mass in kilograms and the volume in cubic metres and the calculator returns the density (mass ÷ volume) in kg/m³.
Mind the units
Keep mass in kilograms and volume in cubic metres — one litre is 0.001 m³, so a small everyday volume is a tiny decimal.
What is a density calculator?
Mass over volume, one clear number
A density calculator turns two measurements — how heavy something is (its mass) and how much space it takes up (its volume) — into a single number: its density, the amount of matter packed into each cubic metre. Density is what separates a feather from a brick of the same size, and it is fixed for a given material at a given temperature. That makes it the go-to figure for identifying materials, predicting whether something will float, and estimating shipping weight from a known volume.
Enter the mass in kilograms and the volume in cubic metres to get the density in kg/m³ instantly.
One short formula: divide the mass by the volume.
ρ = mass ÷ volumeThe Greek letter ρ (rho) is the standard symbol for density. Because density is mass divided by volume, the units follow automatically: kilograms ÷ cubic metres gives kilograms per cubic metre (kg/m³). Note that 1000 kg/m³ is exactly 1 g/cm³, the unit you often see in chemistry — just the same value scaled down by a thousand.
Suppose you have 1 kilogram of water filling a 1-litre bottle.
Convert the volume
One litre is 0.001 m³ — keep volume in cubic metres so the result lands in kg/m³.
Divide mass by volume
1 ÷ 0.001 = 1000 — the mass spread across that volume.
Read the density
1000 kg/m³ — exactly the density of pure water, and equal to 1 g/cm³.
The single density figure tells a surprisingly rich story. The first thing to check is whether it floats: water sits at about 1000 kg/m³, so anything less dense than water (below 1000 kg/m³) floats and anything denser sinks. Ice at 917 kg/m³ floats — which is why icebergs poke above the sea — while aluminium at 2700 kg/m³, iron at 7870 kg/m³, and gold at 19,300 kg/m³ all sink like a stone. Comparing your result against these anchors is also how density is used to identify materials: a metal sample that comes out near 2700 kg/m³ is very likely aluminium, not steel. And because density links mass to volume, it lets you estimate one from the other — handy for working out the shipping weight of a known volume of liquid, or the volume a given mass of material will occupy. The same number, read three different ways, answers buoyancy, identity, and logistics.
The formula is exact, but a couple of practical points are worth keeping in mind.
Temperature, mixtures, and consistent units
Density shifts with temperature and pressure — water is densest near 4 °C and expands when heated or frozen, so published densities assume a stated temperature. The calculator also gives the average density of whatever you measure: a porous or hollow object, or a mixture, returns a blended figure, not the density of the solid material. And the result is only meaningful if mass is in kilograms and volume in cubic metres, never a mix.