Cubic Feet Calculator: Box, Cylinder & Sphere Volume Tool
Use this cubic feet calculator to compute precise three-dimensional volume in cubic feet for rectangular containers, raised planters, and cylindrical columns. Automatically converts between cubic inches, yards, and liters.
The space holds 27 cubic feet (1 cubic yards, or 765 liters).
| Calculated Volume (Cubic Feet) | 27 cu ft |
|---|---|
| Cubic Yards | 1 yd³ |
| Cubic Inches | 46,656 cu in |
| Volume in Liters | 764.6 L |
| Cubic Meters | 0.765 m³ |
📐 Show Formula and Default Assumptions
We believe all home improvement estimates should be transparent and verifiable. Below is the exact math running in this browser tool:
-
Rectangular Box Volume:
Cubic Feet = Length ft × Width ft × Height ftBase standard three-dimensional space formula. -
Cylinder Volume:
Cubic Feet = π × (Radius ft)² × Height ftCalculates round containers, water tanks, and cylindrical piers.
Note: All default assumptions (waste %, coverage rates, container yields) can be adjusted directly in the input fields above to match your project specifications.
How to Measure Three-Dimensional Objects for Volume
- Measure inside dimensions for capacity: If calculating storage containers, planter boxes, or refrigerators, measure inside walls rather than exterior outer shells.
- Keep all measurements in identical units: Convert all three dimensions to feet (or all to inches) prior to calculating.
- For cylindrical containers: Measure the diameter across the circular opening, divide by 2 for the radius, and measure container vertical height.
- Account for wall thickness: In heavy timber raised beds or poured concrete boxes, outer measurements can mislead by several cubic feet.
- Use conversions for fluids: 1 cubic foot equals approximately 7.48 US gallons of water or 28.32 liters.
- Measure inside clearance for appliance and storage units: When calculating cubic feet capacity for pantries, deep freezers, built-in cabinetry, or delivery vans, always measure inside clearance from shelf brackets to door seals, as exterior trim and motor housings can mislead by 20% to 30% of total volume.
- Calculate HVAC airflow cubic capacity: For heating, ventilation, and air conditioning (HVAC) assessments, calculate total room volume in cubic feet (Length × Width × Ceiling Height) and multiply by recommended air changes per hour (ACH) to determine the cubic feet per minute (CFM) rating needed for air purifiers and duct registers.
- Account for container taper: Many plastic storage totes, flower pots, and plastic barrels taper inward from top to bottom. To find accurate internal volume, measure the top width and bottom width, calculate the average, and use that average dimension for your volume formula.
How Cubic Feet Volume is Calculated (Worked Example)
Let us calculate the internal volume of a timber raised garden bed measuring 6 feet long, 3 feet wide, and 18 inches (1.5 ft) deep:
- 1. Length in feet: 6.0 ft.
- 2. Width in feet: 3.0 ft.
- 3. Depth/Height in feet: 18 inches ÷ 12 = 1.5 ft.
- 4. Volume in Cubic Feet: 6.0 × 3.0 × 1.5 = 27.0 cubic feet.
- 5. Unit Conversions: 27.0 cu ft = exactly 1.0 cubic yard = 764.55 liters = 201.97 US liquid gallons.
Cubic Feet Equivalents Across Common Units
| Cubic Feet (Cu Ft) | Cubic Yards (Cu Yd) | Cubic Inches (Cu In) | Gallons (Water) | Liters |
|---|---|---|---|---|
| 1 Cu Ft | 0.037 Cu Yd | 1,728 Cu In | 7.48 Gal | 28.32 L |
| 5 Cu Ft | 0.185 Cu Yd | 8,640 Cu In | 37.40 Gal | 141.58 L |
| 13.5 Cu Ft | 0.500 Cu Yd | 23,328 Cu In | 100.99 Gal | 382.28 L |
| 27 Cu Ft | 1.000 Cu Yd | 46,656 Cu In | 201.97 Gal | 764.55 L |
Frequently Asked Questions About Cubic Feet Calculator
How many cubic inches are in one cubic foot?
There are exactly 1,728 cubic inches in one cubic foot (12" × 12" × 12" = 1,728 cu in). To convert cubic inches to cubic feet, divide by 1,728.
How many gallons of water fit in one cubic foot?
One cubic foot holds approximately 7.4805 US liquid gallons of water. At standard room temperature, one cubic foot of water weighs 62.4 pounds (28.3 kg).
How do I calculate cubic feet if my measurements are in inches?
Multiply Length (in) × Width (in) × Height (in) to obtain total cubic inches, then divide the result by 1,728. For example, a 24" × 24" × 24" box = 13,824 ÷ 1,728 = 8 cubic feet.
How do cubic feet differ from square feet?
Square feet measures two-dimensional surface area (Length × Width), such as a floor or wall. Cubic feet measures three-dimensional volume or capacity (Length × Width × Height), such as the inside of a room, freezer, or garden box.
How many bags of soil make 10 cubic feet?
If using standard 1.0 cubic foot bags of potting soil, you will need exactly 10 bags. If using 1.5 cu ft bags, you need 7 bags (6.67 rounded up). If using 2 cu ft bags, you need 5 bags.
How many cubic feet are in a standard construction dumpster?
Standard roll-off construction dumpsters are measured in cubic yards: a 10-yard dumpster holds 270 cubic feet; a 20-yard dumpster holds 540 cubic feet; a 30-yard dumpster holds 810 cubic feet; and a full 40-yard commercial demolition container holds 1,080 cubic feet.