Definition: A cubic foot (symbol: ft 3) is a unit of volume in the Imperial and United States customary systems of measurement defined as the volume of a cube with side measurements of 1 ft × 1 ft × 1 ft. Tips for Success One cubic foot is the equivalent to approximately 0.02831685 cubic metres, or 28.3169 litres. For example, here's how to convert 5 cubic feet to liters using the formula above. A cubic measurement is the three-dimensional derivative of a linear measure, so a cubic foot is defined as the volume of a cube with sides 1 ft in length. It is equal to 1,728 cubic centimeters, approximately 0.028317 cubic meters, and 28.317 liters. 1 ft³ = 28.316846591991 Liter Example for 3 Cubic Feet: 3 Cubic Feet = 3 (Cubic Feet) 3 … Cubic Feet. Cubic foot. Cubic feet = (0.5 liter) x (1 cubic foot / 28.317 liters) The liters cancel out on the top and bottom, leaving you with 0.5 / 28.317, and giving an answer of 0.018 cubic feet. One cubic foot is equal to 28.316846 liters, so use this simple formula to convert: liters = cubic feet × 28.316846 The volume in liters is equal to the cubic feet multiplied by 28.316846. In metric terms a cubic foot is a cube with sides 0.3048 metres in length.