Cubic Inch Calculator
Calculate volume in cubic inches (and cubic feet) from length, width, and height measured in inches.
Cubic inches measure the volume of small items — boxes, containers, parts, or small pours — where working in feet would leave you with awkward fractions.
How this calculator works
The calculator multiplies length, width, and height together, with all three measurements entered in inches, to get the volume in cubic inches. It then divides that figure by 1,728 to also give you the equivalent in cubic feet, since 1,728 cubic inches always make up exactly one cubic foot.
Formula: Cubic inches = length × width × height (all in inches). Cubic feet = cubic inches ÷ 1,728 (since 12³ = 1,728 cubic inches per cubic foot).
Worked example
A box 24 in long, 12 in wide, and 6 in tall:
- Cubic inches: 24 × 12 × 6 = 1,728 in³
- Cubic feet: 1,728 ÷ 1,728 = 1.0 ft³ exactly
Notes
Working in inches makes sense for small items where feet would be an awkward fraction — a shipping box, a small planter, a container, or a small concrete pour where the dimensions are naturally described in inches rather than feet.
The 1,728 conversion factor is fixed and never changes: it comes directly from a cubic foot being a 12-inch cube, so 12 × 12 × 12 = 1,728 cubic inches always equals exactly 1 cubic foot.
Keep all three measurements in the same unit before multiplying. Mixing inches and feet in the same calculation without converting first will throw the result off by a large factor.
How to use
Measure length, width, and height in inches and enter all three. The calculator returns the volume in cubic inches along with the equivalent in cubic feet, so you can compare a small item’s volume against material that’s priced or sold by the cubic foot.
A pure geometry calculation. Always double-check real-world measurements before ordering material.
Frequently asked questions
What's the formula for cubic inches?
Cubic inches = length × width × height, with all three measurements taken in inches. Multiply the three numbers together and the result is the volume in cubic inches.
How do I convert cubic inches to cubic feet?
Divide the cubic inch total by 1,728. That number comes from a cubic foot being 12 inches on every side — 12 × 12 × 12 = 1,728 cubic inches make up exactly one cubic foot.
Why work in inches instead of feet?
Inches are more practical for small items — boxes, containers, small pours, or parts — where feet would give you an awkward fraction like 0.33 ft. Measuring and entering whole or simple inch values is easier and more accurate for small volumes.
When would I need the cubic feet result from an inch measurement?
Once you have a volume in cubic inches, converting to cubic feet lets you compare it against material sold or priced by the cubic foot — useful when a small container's volume needs to be checked against a larger, feet-based order.
Estimates only. Verify quantities with your supplier before purchasing.