How to Calculate Cubic Inches: Complete Geometric & Engineering Guide
Cubic inches ($\text{in}^3$ or $\text{cu in}$) are a standard unit of three-dimensional volume measurement used extensively throughout the United States and the imperial system. Whether you are shipping freight with FedEx or UPS, calculating engine displacement (CID), planning aquariums, or sizing packaging, mastering how to calculate cubic inches ensures exact volumetric precision.
Rectangular Box Formula
Volume = Length × Width × Height
Multiply all three dimensions in inches to obtain the interior package volume.
Cylinder Formula
Volume = π × Radius² × Height
For pipes, tanks, and round containers. Use half of the diameter as radius.
Engine Displacement (CID)
CID = Bore² × Stroke × 0.7854 × Cylinders
The standard formula used by engine builders and hot rodders.
Standard Cubic Inch Conversion Reference Table
| Target Volume Unit | Exact Conversion Factor | Calculation Rule |
|---|---|---|
| Cubic Feet (ft³) | 1 ft³ = 1,728 in³ | Divide cubic inches by 1,728 |
| US Liquid Gallons (gal) | 1 gal = 231 in³ | Divide cubic inches by 231 |
| Liters (L) | 1 L = 61.0237 in³ | Divide cubic inches by 61.0237 |
| Cubic Centimeters (cc / cm³) | 1 in³ = 16.3871 cm³ | Multiply cubic inches by 16.3871 |
| Cubic Yards (yd³) | 1 yd³ = 46,656 in³ | Divide cubic inches by 46,656 |