Mass Calculator

Unit Conversions

Mass

1 kg = 2.205 lb
1 lb = 453.6 g
1 oz = 28.35 g

Volume

1 L = 1000 cm3
1 gal = 3.785 L
1 ft3 = 28.32 L

Common Densities

Water1.0 g/cm3
Aluminum2.7 g/cm3
Iron/Steel7.87 g/cm3
Gold19.3 g/cm3

Understanding Mass, Density & Volume

The Relationship

Mass, density, and volume are interconnected physical properties. Knowing any two of these values allows you to calculate the third. This relationship is fundamental to physics, chemistry, and engineering.

Core Formulas

Mass = Density x Volume
Density = Mass / Volume
Volume = Mass / Density

Mass vs Weight

Mass

  • Amount of matter in an object
  • Constant everywhere in universe
  • Measured in kg, g, lb (mass)
  • Does not change with gravity

Weight

  • Force of gravity on mass
  • Varies with gravitational field
  • Measured in N, lb (force)
  • W = m x g (g = 9.81 m/s2)

Material Densities

Materialg/cm3kg/m3lb/ft3
Air (STP)0.00121.20.075
Wood (Oak)0.7575047
Water1.0100062.4
Concrete2.42400150
Copper8.968960559
Lead11.3411340708

Practical Applications

Engineering

  • Structural load calculations
  • Material selection
  • Shipping weight estimates
  • Vehicle payload limits

Science

  • Chemical reactions
  • Buoyancy calculations
  • Fluid dynamics
  • Material identification

Buoyancy

Objects float when their density is less than the fluid they are in. A steel ship floats because the average density (steel + air inside) is less than water. Understanding this relationship is crucial in naval architecture and fluid mechanics.

Frequently Asked Questions

How do I calculate mass from density and volume?

Use the formula: Mass = Density x Volume. For example, if you have 500 cm³ of aluminum (density 2.7 g/cm³), the mass is 500 x 2.7 = 1,350 grams (1.35 kg).

What is the difference between mass and weight?

Mass is the amount of matter in an object and stays constant everywhere. Weight is the gravitational force on that mass and changes with gravity. On the Moon (1/6 Earth gravity), you'd weigh less but have the same mass.

Why does density matter?

Density determines if objects float or sink (less dense than water = floats), helps identify materials, and is essential for calculating shipping weights, structural loads, and material quantities for projects.

What are common density units?

Common units include g/cm³ (grams per cubic centimeter), kg/m³ (kilograms per cubic meter), and lb/ft³ (pounds per cubic foot). Water has a density of 1 g/cm³ = 1,000 kg/m³ = 62.4 lb/ft³.