Convert inches to meters
One inch equals exactly 0.0254 meters. Multiply each package dimension by 0.0254, then multiply length × width × height. A 24 × 18 × 16 inch carton is about 0.6096 × 0.4572 × 0.4064 meters, or roughly 0.1133 CBM.
Multiply by the number of identical cartons to find shipment volume. If several carton sizes are present, calculate each group separately and add the CBM totals.
Avoid an imperial-to-metric shortcut error
Do not divide cubic inches by a linear conversion factor. Volume uses the conversion factor three times because length, width and height are each converted. The safe approach is to convert dimensions first or use a verified cubic-inch-to-cubic-meter factor.
When your supplier provides dimensions in inches but your freight quote is in CBM, keep both the source measurements and converted result in the packing record so discrepancies are easier to audit.
Measure the shipment as tendered
Measure the finished outer carton at its widest points. Handles, straps, protrusions and deformation can change the occupied space, especially when many pieces are stacked together.
For a freight booking, the forwarder may remeasure cargo. Treat your calculation as a pre-booking estimate and reconcile any difference against the final packed dimensions.
Keep the cubic conversion separate from measurement rounding
The 24 × 18 × 16 inch example contains 6,912 in³. Multiplying by the exact factor 0.000016387064 gives 0.113267386368 m³; ten identical cartons total 1.13267386368 m³. If you round the one-carton display to 0.1133 before multiplying, you get 1.133, a different displayed total.
For physical CBM, convert the measured sides without inserting parcel-tariff rounding. If a quote requires each side rounded up first, record that as a separate rating assumption. The same package can legitimately have measured volume and rated volume that differ.
Reproduce the calculation
Use the related Cargoivo calculator with your own shipment dimensions, weight, or quantity.
Open CBM Calculator →Cargoivo provides educational planning information, not a freight quote, engineering approval, customs advice, or carrier commitment. Verify current service rules, equipment specifications, and commercial terms before shipping.