Use the formula for the shape or substance
Measure length, width, and height for a rectangular solid
Calculate volume with V = l × w × h
Measure radius for a cylinder
Calculate volume with V = πr²h
Measure radius for a sphere
Calculate volume with V = 4/3 πr³
Use mass and density if volume is unknown
Calculate volume with V = m ÷ d
Use a graduated cylinder for liquids
Read the liquid level at eye level
Use water displacement for irregular objects
Subtract initial water level from final water level
Convert units as needed
Express volume in cubic units or liters