The cubic foot (symbol ft³ or cu ft) is an imperial and US customary (non-metric) unit of volume, used in the United States and the United Kingdom. It is defined as the volume of a cube with sides of one foot (0.3048 m) in length, or exactly 28.316846592 L, which is very close to ⁠1/35⁠ of a cubic metre).

The IEEE symbol for the cubic foot is ft³. The following abbreviations are used: cubic feet, cubic foot, cubic ft, cu feet, cu foot, cu ft, cu.ft, cuft, cb ft, cb.ft, cbft, cbf, feet³, foot³, ft³, feet/-3, foot/-3, ft/-3.^{[citation needed]}

Larger multiples are in common usage in commerce and industry in the United States:

The IEEE symbol for the cubic foot per second is ft³/s. The following other abbreviations are also sometimes used:

The flow or discharge of rivers, i.e., the volume of water passing a location per unit of time, is commonly expressed in units of cubic feet per second or cubic metres per second.

Cusec is a unit of flow rate, used mostly in the United States in the context of water flow, particularly of rivers and canals.

Conversions: 1 ft³s⁻¹ = 0.0283168 m³/s = 28.3168 L/s = 1.699011 m³/min = 1,699.011 L/min

The IEEE symbol for the cubic foot per minute is ft³/min. The following abbreviations are used: