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Cubic Feet Calculator – Calculate Volume in Cubic Feet (ft³)

Cubic Feet Volume

All dimensions in the same unit. Result in cubic feet.

The Cubic Feet Calculator computes the volume of common 3D shapes – rectangular boxes (rooms, shipping containers), cylinders (pipes, tanks), and spheres (balloons, storage vessels). It automatically converts input units (feet, inches, yards, meters, cm) to feet and outputs volume in cubic feet. This is essential for construction, moving, shipping, landscaping, and home improvement projects where volume measurements are critical.

Cubic Feet Formulas

Rectangular (Box / Room): V = L × W × H

Cylinder (Pipe / Tank): V = π × r² × H

Sphere (Ball / Vessel): V = (4/3) × π × r³

All dimensions must be in the same unit (feet, inches, etc.). The calculator converts them to feet before applying the formula, so you don't have to worry about unit conversions. For example, a box that is 60 inches long, 48 inches wide, and 36 inches high: convert each to feet (5 ft, 4 ft, 3 ft) → volume = 5×4×3 = 60 cubic feet.

Real‑World Applications

  • Moving and storage: Estimate how many boxes fit in a truck or storage unit.
  • Construction: Concrete volume for foundations, soil for landscaping.
  • Shipping and freight: Calculate cargo volume for LTL (less‑than‑truckload) shipments.
  • Aquariums and tanks: Determine water capacity or filter sizing.
  • HVAC: Calculate air volume for duct sizing and ventilation.
Understanding Cubic Feet as a Unit of Volume

One cubic foot (ft³) is the volume of a cube measuring 1 foot on each side. It equals approximately 28.3168 liters, 7.48052 US gallons, or 0.0283168 cubic meters. In construction, ready‑mix concrete is often sold by the cubic yard (27 ft³). Moving companies charge based on cubic feet of belongings. The calculator helps you translate real‑world dimensions into this standard unit.

For shipping, dimensional weight (DIM weight) often uses cubic feet divided by a factor (e.g., 139 for domestic US) to determine billable weight. By knowing the cubic feet of your package, you can estimate shipping costs.

How to Measure for Cubic Feet (Step‑by‑Step)

Measuring for cubic feet is straightforward: use a tape measure to find length, width, and height (or radius and height for cylinders). If your measurements are in feet, multiply directly. If in inches, divide each dimension by 12 before multiplying. For centimeters, divide by 30.48. Our calculator does this conversion automatically. Always measure the interior dimensions when calculating usable volume (e.g., inside a box or room).

Common Mistakes When Calculating Cubic Feet

  • Mixing units: Using inches for one dimension and feet for another – our calculator prevents this by using a single unit for all inputs.
  • Forgetting to convert inches to feet: 12 inches = 1 foot. If you have 60 in × 48 in × 36 in, do not multiply raw inches (103,680 in³) and call it cubic feet; you must divide by 12³ = 1728. Our calculator handles this.
  • Using diameter instead of radius for cylinders: The formula requires radius. If you have diameter, divide by 2 first.
  • Ignoring empty space: When packing a moving truck, the actual usable cubic feet is less than the truck's listed capacity due to wheel wells and irregular shapes.

Use this cubic feet calculator for any project that requires volume estimation – from home DIY to professional logistics. The step‑by‑step breakdown ensures accuracy and builds confidence in your measurements.

Step‑by‑Step Manual Example

Rectangular box: 60 in × 48 in × 36 in:

Convert each to feet: 60/12 = 5 ft, 48/12 = 4 ft, 36/12 = 3 ft.

Volume = 5 × 4 × 3 = 60 cubic feet.

Cylinder: radius = 2 ft, height = 5 ft: V = π × 2² × 5 = 3.1416 × 4 × 5 = 62.83 cubic feet.

Sphere: radius = 3 ft: V = (4/3) × π × 3³ = (4/3) × 3.1416 × 27 = 113.1 cubic feet.

Practical Conversion Table

FromTo Cubic Feet
1 cubic inch0.000578704 ft³
1 cubic yard27 ft³
1 cubic meter35.3147 ft³
1 US gallon0.133681 ft³

Frequently Asked Questions about Cubic Feet

What is a cubic foot?
A cubic foot is a unit of volume equal to the space occupied by a cube measuring 1 foot on each side. It is commonly used in construction, shipping, and storage to measure the capacity of containers, rooms, or tanks.
How do I calculate cubic feet for a rectangular space?
Multiply length × width × height (all in feet). If your measurements are in inches, first convert to feet by dividing by 12. Our calculator does this automatically.
How many cubic feet are in a cubic yard?
1 cubic yard = 27 cubic feet. This conversion is useful for ordering soil, concrete, or mulch.
What is the formula for cubic feet of a cylinder?
Volume = π × radius² × height (radius and height in feet). Our calculator supports this shape.
Can I calculate cubic feet for irregular shapes?
For irregular shapes, break them down into smaller rectangular or cylindrical sections, calculate each volume, then add them together.