Methodology and formulas

Transparent formulas, assumptions, units and limitations.

Core formulas

• Material cost = used weight × spool price / net spool weight.
• Energy cost = time × average power / 1000 × electricity price.
• Machine use = operating time × chosen hourly machine rate.
• Filament length follows from cylinder volume and material density.
• Expected failure cost includes probability and average interruption stage.

Limitations

Slicer and G-code estimates vary by software, profile and file comments. Average power should be measured. Filament density and empty-spool weight vary by product.