A cubic foot is the volume of a cube one foot on every side; for a rectangular box it is length × width × height with all three measured in feet. Work out cubic feet from any units — inches, feet, cm, metres or yards — for a box or a cylinder, with cubic yards, cubic metres, litres and gallons alongside.
Three steps, any unit in, cubic feet out.
Use Box for anything rectangular — a room, a crate, a fridge, a shipping carton. Use Cylinder for a tank, tube, barrel or pipe, where you enter a radius and a height instead.
Set the unit to whatever you measured in — inches, feet, centimetres, metres or yards — then type the dimensions. The calculator converts everything to feet before it multiplies, so you never have to do the conversion yourself.
Cubic feet is the headline number, with cubic inches, cubic yards, cubic metres, litres and gallons beside it.