Estimate mass from rectangular dimensions and density, or density from measured mass, for solid blocks and ideal closed hollow shells.
How to use this tool
- Choose mass from density or density from a measured per-object mass.
- Choose a solid block or an ideal closed uniform-wall shell. Enter outside dimensions and wall thickness if needed.
- Enter the actual material density or the measured mass with its unit, and the number of identical objects.
- Select Calculate. Read material volume and per-object mass separately from the total quantity mass.
Formula and unit basis
Mass = material volume × material density. A solid block uses L × W × H. A closed, uniform-wall hollow shell uses LWH − (L−2t)(W−2t)(H−2t). Reverse density = measured mass ÷ material volume.
Worked examples
A solid 20 cm × 10 cm × 5 cm block has volume 0.001 m³. At an assumed 2,400 kg/m³, its mass is 2.4 kg. A closed 40 cm × 30 cm × 25 cm shell with 0.5 cm walls has material volume 0.002856 m³.
Assumptions and interpretation
Density must match composition, moisture, temperature and bulk/solid state. The hollow model is a closed ideal shell, not an open carton or folded corrugated package. Contents, fittings, packaging and voids need separate treatment. Results are mass in kg and lb, not a carrier dimensional-weight charge or a structural capacity.
Project guides
- Choose the Right Density for a Solid Rectangular Block
- Solid Blocks, Hollow Boxes and Shipping Weight: Three Different Calculations
Choose the related tool for the next question
Explore Construction calculators or return to the GreenCalc home page for other subjects.
Frequently asked questions
Can the tool calculate density from a known mass?
Yes. Select density from measured mass and enter the mass of one object and its material geometry.
Does the hollow option represent any shipping carton?
No. It represents an ideal closed six-wall shell with uniform thickness; real packaging may require measured tare mass.
Is the mass output a carrier billable weight?
No. Carrier dimensional-weight and billing rules are a separate calculation.