By Zencalcy Editorial TeamLast reviewed About us
Weight is volume times density, so a box only needs three measurements and the density of what it is made of or filled with. This calculator reports both the solid weight and, for a hollow box, the weight of the walls at a given thickness.
Estimate the weight of a solid or hollow box from its size and material.
V = L × W × H W = V × ρ
Dimensions are in inches and convert to cubic feet by dividing by 1,728. Density is in lb/ft³: water is 62.4, steel 490, oak about 47 and dry sand 100. A hollow box's walls are treated as six flat panels with no overlap correction.
| Symbol | Meaning |
|---|---|
| L, W, H | Outside dimensions in inches. |
| t | Wall thickness in inches (0 for solid). |
| ρ | Material density in pounds per cubic foot. |
| W | Estimated weight in pounds and kilograms. |
The outside volume is 5,184 cu in, or 3.0 cu ft. With half-inch walls the material volume is about 0.33 cu ft, so a 34 lb/ft³ plywood crate weighs roughly 11 lb before contents.
Continue with the Board Foot Calculator, Cubic Yard Calculator, Gallons per Square Foot Calculator, or the Square Feet to Cubic Yards Calculator — or browse more construction converters and all construction calculators.
Measure the smallest box it fits inside and expect the estimate to run high, or use water displacement for a solid object.
Results use standard construction estimating arithmetic: volumes from measured area and depth, unit weights from published material densities, and code-referenced spans or clearances where the page names a code. Quantities are rounded up to whole saleable units and include the stated waste allowance. These tools are planning aids, not structural design, and do not replace a licensed engineer, a local code check, or a contractor's site measurement.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026