Measure length (ft)
Measure width (ft)
Measure height (ft)
Multiply: cubic feet = length × width × height
If dimensions are in inches: convert to feet by dividing each by 12, then multiply
If dimensions are in centimeters: convert to feet by dividing by 30.48, then multiply
For a rectangular prism: cubic feet = L × W × H
For a cylinder: cubic feet = π × (radius in ft)² × height in ft
For a sphere: cubic feet = (4/3) × π × (radius in ft)³
For a cone: cubic feet = (1/3) × π × (radius in ft)² × height in ft
For an irregular space: split into simpler shapes, calculate each volume in cubic feet, then add