How to Calculate Density: Step-by-Step
A detailed guide walking through the calculation process with worked examples and common mistakes to avoid.
Read Guide →Master the physics formula D=M/V with step-by-step explanations, interactive tools, and real-world examples
The density formula calculates how much mass is contained in a given volume:
Example: An object with a mass of 50g and volume of 10 mL has a density of 5 g/mL
Calculate density, mass, or volume with automatic unit conversion
Where:
Solve for Mass:
m = ρ × V
Solve for Volume:
V = m ÷ ρ
Density measures how tightly packed matter is in a given space. It tells you how much "stuff" (mass) is packed into a certain volume:
Mass of material including the space between particles (used for granular materials)
Mass of just the solid particles, excluding the voids between them
Ratio of substance density to water density (dimensionless)
Mass divided by volume including all voids (pores and gaps)
1 g/mL
Water is the standard reference. Most substances either float or sink based on comparison to water's density.
2.7 g/cm³
Lightweight metal used in aircraft and beverage cans because of its low density-to-strength ratio.
19.3 g/cm³
Highly dense precious metal. A cube of gold the size of a Rubik's cube weighs about 5 kg!
~0.03 g/cm³
Very low density foam. Floats easily and provides excellent insulation and cushioning.
Learn more about density with our comprehensive guides
A detailed guide walking through the calculation process with worked examples and common mistakes to avoid.
Read Guide →Understand the fundamental differences between these three related but distinct concepts.
Read Guide →Master different density units and learn how to convert between g/mL, kg/m³, and other measurements.
Read Guide →Discover how density calculations are used in engineering, chemistry, physics, and everyday life.
Read Guide →Density measures how much mass is packed into a certain volume. It answers the question: "How tightly packed is the material?" A dense object feels heavy for its size, while a light object feels light for its size.
Water's density of 1 g/mL is actually defined by convention. Scientists chose water at 4°C as the reference standard because it's a common, stable substance. This makes water density equal to 1 by definition, and it serves as the reference point for comparing other substances.
Most substances become less dense when heated because the particles move faster and spread out. Water is an exception: it's most dense at 4°C and becomes less dense both above and below this temperature, which is why ice floats.
No. Two objects can have the same mass but different densities if they have different volumes. For example, a kilogram of feathers has a much larger volume than a kilogram of lead, so the feathers have lower density.
Weight depends on gravity, while density does not. An object weighs less on the Moon than on Earth, but its density remains the same. Density is an intrinsic property of a material, while weight depends on the gravitational field.
Density is used in many applications: determining if objects float (ships), designing materials (aerospace), quality control in manufacturing, environmental science, medicine (specific gravity of urine/blood), and cooking (adjusting recipes for altitude).
Objects float if their density is less than the fluid they're in (e.g., less than 1 g/mL in water), and sink if their density is greater. This is why wood floats but rocks sink in water.
You can change an object's density by changing its volume (compressing or expanding it) or by changing its mass (adding or removing material). Temperature changes also affect density for most materials.
Convert between g/mL, kg/m³, lb/ft³, and more.
Find the density of common materials instantly.
Calculate mass from density and volume.
Calculate volume from density and mass.