Density Calculator - Free Online Physics Tool

Density Calculator

Calculate density, mass, or volume using ρ = m/V formula

Find Density (ρ)

Find Mass (m)

Find Volume (V)

Mass (m)

Volume (V)

cm³

m³

Density (ρ)

g/cm³

kg/m³

lb/ft³

Volume (V)

cm³

m³

Mass (m)

Density (ρ)

g/cm³

kg/m³

lb/ft³

Common Materials (Optional)

This will only fill the density field for reference. You still need to enter other values.

Density (ρ)

0.00 g/cm³

Enter values in the fields above to calculate

Formula Used

ρ = m/V

Relative to Water

Material Type

Unknown

Density Formulas

ρ = m ÷ V

ρ (rho): Density (mass per unit volume)

m: Mass of the object

V: Volume of the object

Rearrange for: m = ρ × V | V = m ÷ ρ

SI unit: kg/m³ | Common unit: g/cm³

People Also Ask

🤔 What is density and how is it calculated?

Density is mass per unit volume: ρ = m/V. It measures how much matter is packed into a space. Higher density = more mass in same volume.

🔍 Why does ice float on water?

Ice density (0.92 g/cm³) < Water density (1.00 g/cm³). Less dense objects float on more dense fluids. Ice expands when freezing, decreasing density.

⚡ How to find volume if I know mass and density?

Rearrange formula: V = m/ρ. Divide mass by density. Example: 100g gold (ρ=19.3 g/cm³) has V = 100/19.3 = 5.18 cm³.

📏 What's difference between density and specific gravity?

Density is absolute (g/cm³). Specific gravity is relative density compared to water (dimensionless). SG = ρ_substance/ρ_water.

🎯 How does temperature affect density?

Most substances expand when heated (volume ↑), decreasing density. Water is densest at 4°C. Gases are highly temperature-dependent.

🔥 What are real-world applications of density?

Ship building (buoyancy), oil separation, air density for aviation, material selection in engineering, geology (mineral identification), cooking.

What is Density?

Density is a fundamental physical property that measures how much mass is contained in a given volume. It's defined as mass per unit volume and is typically expressed in units like grams per cubic centimeter (g/cm³) or kilograms per cubic meter (kg/m³). The density of a substance determines whether it will float or sink in another substance.

Why is Density Important?

Density helps identify materials, predict buoyancy, design structures, and understand material properties. It's crucial in fields like material science, engineering, geology, fluid dynamics, and manufacturing.

Key density concepts:

Intensive property: Doesn't depend on amount of substance
Characteristic property: Helps identify pure substances
Buoyancy determinant: Objects less dense than fluid float
Temperature dependent: Most substances less dense when hot
Pressure dependent: Gases more dense under pressure

How to Use This Calculator

This calculator finds any one variable when you know the other two:

Three Calculation Modes:

Find Density: Enter mass and volume → Get ρ = m/V
Find Mass: Enter density and volume → Get m = ρ × V
Find Volume: Enter mass and density → Get V = m/ρ

The calculator provides:

Accurate calculation using ρ = m/V formula
Multiple unit conversions (g, kg, lb, cm³, m³, L, etc.)
Relative density comparison to water (specific gravity)
Material type suggestion based on density range
Step-by-step formula display
Common material presets for reference (optional)

Common Material Densities

Reference densities of common materials at room temperature (20°C):

Material	Density (g/cm³)	Density (kg/m³)	Relative to Water	State
Air (STP)	0.0012	1.2	0.0012×	Gas
Wood (Oak)	0.75	750	0.75×	Solid
Water (4°C)	1.000	1000	1.00×	Liquid
Aluminum	2.70	2700	2.70×	Solid
Iron/Steel	7.87	7870	7.87×	Solid
Copper	8.96	8960	8.96×	Solid
Lead	11.34	11340	11.34×	Solid
Mercury	13.53	13530	13.53×	Liquid
Gold	19.32	19320	19.32×	Solid
Osmium	22.59	22590	22.59×	Solid

Density Range Guide:

Very low density (<0.1 g/cm³): Aerogels, foams, gases
Low density (0.1-1 g/cm³): Wood, plastics, cork, ice
Medium density (1-5 g/cm³): Water, most liquids, aluminum, glass
High density (5-15 g/cm³): Iron, copper, lead, silver
Very high density (>15 g/cm³): Gold, tungsten, platinum, osmium

Common Questions & Solutions

Below are answers to frequently asked questions about density calculations:

Calculation & Formulas

How do I calculate density for irregular shaped objects?

For irregular objects, measure mass with scale and volume by displacement:

Water Displacement Method:

Measure mass (m): Use digital scale
Fill graduated cylinder with water, note initial volume V₁
Submerge object completely (no air bubbles)
Note final volume V₂ (water level rises)
Calculate volume: V = V₂ - V₁
Calculate density: ρ = m ÷ (V₂ - V₁)

Example: Object mass = 50g, V₁ = 30mL, V₂ = 40mL → V = 10mL = 10cm³ → ρ = 50g/10cm³ = 5 g/cm³.

How to convert between different density units?

Common density unit conversions:

Density Unit Conversions:

1 g/cm³ = 1000 kg/m³

1 g/cm³ = 0.0361 lb/in³

1 g/cm³ = 62.43 lb/ft³

1 kg/m³ = 0.001 g/cm³

1 lb/ft³ = 0.0160 g/cm³

1 lb/in³ = 27.68 g/cm³

Conversion formula: Multiply by conversion factor. Our calculator handles all conversions automatically based on your selected units.

Practical Applications

How is density used in shipbuilding and buoyancy?

Archimedes' principle: Buoyant force = weight of displaced fluid. Ships float because their average density is less than water.

Ship Part	Material	Density (g/cm³)	Purpose
Hull	Steel	7.87	Strength, but hollow so average density < 1
Ballast	Water/Concrete	1.0-2.4	Adjusts draft and stability
Life Jackets	Foam	0.05-0.2	Very low density for buoyancy
Superstructure	Aluminum	2.70	Lightweight for upper parts
Propeller	Bronze	8.8	Dense for strength underwater

Key calculation: Ship's average density = Total mass ÷ Total volume (including air spaces). Must be < 1.025 g/cm³ (seawater) to float.

How do density differences separate materials in industry?

Density separation (gravity separation) uses density differences to separate mixtures:

Density Separation Methods:

Oil-water separation: Oil (0.8-0.9 g/cm³) floats on water (1.0 g/cm³)
Mineral processing: Heavy liquids separate ores by density
Recycling: Plastics separated in water (sink/float test)
Food industry: Separating solids from liquids, cream from milk
Wastewater treatment: Settling tanks use density differences
Gold panning: Gold (19.3) settles, lighter materials wash away

Centrifugation: Spinning increases effective "gravity," enhancing density-based separation (blood components, DNA extraction).

Science & Nature

Why is water densest at 4°C? What are implications?

Water's unique density-temperature relationship supports life on Earth:

Water Density Anomaly:

0°C (ice): 0.9168 g/cm³ - floats on water
4°C (liquid): 1.0000 g/cm³ - maximum density
20°C (liquid): 0.9982 g/cm³
100°C (boiling): 0.9584 g/cm³

Hydrogen bonding causes expansion when freezing, creating less dense ice.

Ecological importance: Lakes freeze top-down. Ice insulates water below, allowing aquatic life to survive winter. Without this anomaly, lakes would freeze solid bottom-up, killing most aquatic organisms.

How does air density affect weather and aviation?

Air density varies with altitude, temperature, and humidity, affecting weather and flight:

Condition	Effect on Density	Impact
High altitude	Decreases (less pressure)	Less lift, longer takeoff
High temperature	Decreases (expands)	Less engine power, longer runway
High humidity	Slightly decreases (H₂O lighter than air)	Small performance decrease
Low pressure system	Decreases	Stormy weather, reduced aircraft performance
High pressure system	Increases	Clear weather, better aircraft performance

Aviation calculation: Density altitude = pressure altitude corrected for temperature. High density altitude = "thin air" = reduced aircraft performance. Pilots must calculate for safe operations.