How to calculate the cubic feet of a box
Cubic feet is the unit freight carriers, moving companies and storage services use to measure space. Calculating it for a box takes one multiplication and one division.
The formula
Why 1,728? A cubic foot is 12 inches × 12 inches × 12 inches, which is 1,728 cubic inches. Measuring in inches and dividing converts the result to cubic feet.
Example: a standard shipping box
A box measures 18 × 14 × 12 inches.
- Multiply the three sides: 18 × 14 × 12 = 3,024 cubic inches.
- Divide by 1,728: 3,024 ÷ 1,728 = 1.75 cubic feet.
If you measured in feet
Just multiply. A crate that's 4 × 3 × 2.5 feet is 30 cubic feet. If some measurements are in feet and inches, convert everything to inches first: 3 ft 6 in is 42 inches.
If you measured in centimeters
Multiply to get cubic centimeters, then divide by 28,317 for cubic feet. Or divide by 1,000,000 for cubic meters, and multiply cubic meters by 35.315 for cubic feet. A 50 × 40 × 30 cm box is 60,000 cm³, which is 0.06 m³ or about 2.12 cubic feet.
Inside or outside dimensions?
It depends on the question. For how much a box holds, use the inside dimensions. For how much space it takes up in a truck, warehouse or storage unit, use the outside. The difference is small for one box but adds up across a pallet or trailer.
For a whole shipment
Calculate one box, then multiply by the number of boxes. Twenty of the 1.75 cu ft boxes above make 35 cubic feet. If boxes are different sizes, calculate each size separately and add them up.
For LTL freight, carriers usually measure the whole pallet, including the pallet itself and any overhang, and use that to calculate density and freight class.
Useful conversions
| Unit | Equals |
|---|---|
| 1 cubic foot | 1,728 cubic inches |
| 1 cubic foot | 28.317 liters |
| 1 cubic yard | 27 cubic feet |
| 1 cubic meter | 35.315 cubic feet |
Common mistakes
The classic slip is dividing by 144 instead of 1,728. 144 converts square inches to square feet, which is area, not volume. Another is mixing units, such as a length in feet and a width in inches. Convert everything to one unit before multiplying.