How to estimate part volume and weight from an STL

Volume from the mesh

A watertight STL's volume is computed by summing signed tetrahedron volumes over its triangles - slicers, CAD packages and our calculator all do this instantly. Weight = volume x material density.

Densities that matter

PLA 1.24, PETG 1.27, ABS 1.05, nylon 1.14, standard resin ~1.1, PA12 1.01, 316L stainless 7.9, aluminum 2.7 g/cm³. Same file, wildly different weights - a 100 cm³ part is 124 g in PLA but 790 g in stainless.

Solid vs printed weight

FDM parts print with infill: a 20% infill part weighs roughly 35-55% of solid depending on walls. Resin, SLS and metal parts print effectively solid. Estimate solid first, then scale for infill.

Skip the manual math

Drop your STL or STEP into our calculator - volume, dimensions, weight and estimated machine time appear automatically, priced with your rates.