Cubic feet measure how much space something takes up or holds: the capacity of a refrigerator, the size of a moving box, the volume of a storage unit, a bag of potting mix or a raised bed. This calculator works out cubic feet for rectangular boxes and cylinders from measurements in inches, feet, yards, centimeters or meters, and converts the answer to the other common volume units.
How to use the cubic feet calculator
- Choose Box / rectangular or Cylinder.
- Enter the dimensions and pick a unit for each one; you can mix inches and feet.
- Enter a quantity if you have several identical items, such as a stack of boxes.
- Read the total in cubic feet, with cubic inches, cubic yards, cubic meters, liters and US gallons alongside.
Cubic feet formulas
Every dimension must be in feet before multiplying. If all three are in inches, it is easier to multiply them first and divide once:
Worked examples
Moving box, 24 × 18 × 16 in: 24 × 18 × 16 = 6,912 in³; 6,912 ÷ 1,728 = 4 ft³.
Three round planters, 12 in across and 36 in tall: π × 0.5² × 3 = 2.356 ft³ each, or 7.07 ft³ for all three — about 52.9 gallons of potting mix.
Mixed units, a chest 6 ft × 30 in × 16 in: 6 × 2.5 × 1.333 = 20 ft³.
Common moving box sizes
| Box | Typical dimensions | Volume |
|---|---|---|
| Small | 16 × 12 × 12 in | 1.33 ft³ |
| Medium | 18 × 18 × 16 in | 3.0 ft³ |
| Large | 18 × 18 × 24 in | 4.5 ft³ |
| Extra-large | 24 × 18 × 24 in | 6.0 ft³ |
Exact sizes vary by manufacturer, but these are close to the standard US moving boxes. Movers often estimate a household’s total cubic footage and then convert it to truck size, so adding up your boxes with the quantity field gives a useful starting figure.
Volume conversions for one cubic foot
| Unit | Equivalent of 1 ft³ |
|---|---|
| Cubic inches | 1,728 in³ |
| Cubic yards | 0.0370 yd³ (1/27) |
| Liters | 28.32 L |
| Cubic meters | 0.02832 m³ |
| US gallons | 7.48 gal |
Where cubic feet show up
Appliance makers list refrigerator and freezer capacity in cubic feet; a typical full-size refrigerator is about 18 to 25 ft³. Bagged soil, mulch and compost are sold in 0.75, 1, 1.5, 2 and 3 cubic foot bags. Shipping companies may charge by dimensional weight, which starts from a package’s cubic size rather than its scale weight, so a large light box can cost more than its weight suggests. For volumes measured in gallons or liters — water tanks, aquariums and cisterns — the tank volume calculator handles partial fill levels, and for bulk landscape materials sold by the yard, use the cubic yards calculator.
Frequently asked questions
How do I calculate cubic feet from inches?
Multiply length × width × height in inches to get cubic inches, then divide by 1,728 (which is 12 × 12 × 12). A box measuring 24 × 18 × 16 inches holds 6,912 cubic inches, or exactly 4 cubic feet.
How do I find the cubic feet of a cylinder?
Use π × radius² × height with every measurement in feet. A drum 2 feet across and 3 feet tall holds π × 1² × 3 ≈ 9.42 cubic feet.
How many gallons are in a cubic foot?
About 7.48 US gallons, because a US gallon is defined as 231 cubic inches and 1,728 ÷ 231 ≈ 7.48. A cubic foot is also about 28.3 liters.
How many cubic feet is a 10 × 10 storage unit?
Storage units are named by floor size, so you also need the ceiling height. With an 8-foot ceiling, a 10 × 10 unit holds 10 × 10 × 8 = 800 cubic feet, though you can rarely pack it completely.
How do I convert cubic feet to cubic yards?
Divide by 27. For example, 54 cubic feet is 2 cubic yards. Bulk materials such as soil and concrete are usually ordered in cubic yards.