3D Print Filament Weight & Cost Calculator

Filament is manufactured as a cylinder, so its volume follows the standard cylinder formula: volume = π × (diameter ÷ 2)² × length. Multiplying that volume by the material's density converts it directly to a weight, and dividing weight by density and back through the same cross-section recovers length instead — so this calculator solves in either direction depending on whether you know the length (e.g. from a slicer's estimate) or the weight (e.g. what's left on a partial spool).

Material density is a plain, editable input rather than a hardcoded fact, since it varies by brand and blend even within the same material — the default (1.24 g/cm³) is PLA's commonly published figure, with PETG around 1.27, ABS around 1.04, and TPU around 1.21 as reference points to swap in.

Cost is simply the computed weight, converted to kilograms, times whatever you pay per kilogram — a number only you know, not looked up, since filament pricing varies by seller and changes over time.