Clay Weight Calculator — Solid & Hollow Sculpture

How Clay Weight Calculation Works

Wet weight = Clay volume × wet density

The calculator works out the volume of your chosen shape from its outside dimensions, subtracts the hollow interior when you give a wall thickness, then multiplies by the wet plastic density to get the wet weight.

The bone-dry weight is the wet weight minus the water of plasticity (about 20% of the mass for a plastic clay body), since drying only removes water. The fired weight is the bone-dry weight minus the loss on ignition — the chemically bound water, carbon dioxide and organics driven off in the kiln (roughly 5-8% of the dry mass). Because firing can only remove mass, the fired weight is always lower than the bone-dry weight, giving a total wet-to-fired loss of roughly a quarter (about 25%). Linear shrinkage changes the finished size but not the mass, so it is reported separately.