📦 Size to Weight Calculator (Rectangular Box)
Estimate the total weight of a rectangular box or solid block based on its dimensions and the density of the material inside.
in
in
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lb/ft³
What this calculator does
This tool estimates the total weight of a rectangular box or block of material using its outer dimensions and the density of the material filling it.
The formula
Volume = length × width × height (converted to cubic feet), then Weight = volume × density. The default density (62.4 lb/ft³) is water; swap in the density of your actual material (wood, metal, stone, packed goods, etc.) for an accurate estimate.
This calculation assumes a solid, uniformly dense fill with no hollow space or packaging air gaps. For general planning and shipping estimates only.
Last reviewed August 2026