CBM Calculator (Inches)
Enter your box dimensions in inches to get the CBM (cubic meters) and cubic feet of your carton.
CBM from inches
This calculator takes a box measured in inches and returns its volume in cubic meters (CBM) and cubic feet. Inches are the everyday unit for cartons in the US, but ocean and air paperwork is filed in CBM, so the job here is a clean unit conversion, not just a multiplication.
How it works
Multiply the three sides to get cubic inches, then convert. One inch is exactly 25.4 mm, so one cubic inch is 25.4³ = 16,387.064 mm³, and one cubic meter holds 61,023.74 cubic inches. The formula is:
CBM = (L × W × H in inches) ÷ 61,023.74
For cubic feet, divide cubic inches by 1,728 (since 12³ = 1,728).
Worked example
Using the page defaults, a carton 40 × 30 × 24 in:
- Cubic inches:
40 × 30 × 24 = 28,800 in³ - CBM:
28,800 ÷ 61,023.74 = 0.472 CBM - Cubic feet:
28,800 ÷ 1,728 = 16.667 ft³
So one carton is 0.472 CBM. Ten identical cartons would be 4.72 CBM. Always measure to the outer edge of the box at its widest point, including any bulge, and round each side up to the nearest whole or half inch before multiplying, undersizing here compounds across a full load.
Inch-to-CBM reference
| Box (in) | Cubic in | CBM | Cubic ft |
|---|---|---|---|
| 12 × 12 × 12 | 1,728 | 0.028 | 1.000 |
| 24 × 18 × 18 | 7,776 | 0.127 | 4.500 |
| 40 × 30 × 24 | 28,800 | 0.472 | 16.667 |
| 48 × 40 × 36 | 69,120 | 1.133 | 40.000 |
If you would rather work in larger imperial units, the CBM calculator in feet skips the 1,728 step. For a side-by-side with metric inputs, see the CBM calculator in cm or the main CBM calculator. To go straight from cubic inches without the metric step, the cubic feet to CBM converter handles a single volume figure.