Decide whether you need consumption cost or a purchase order
A print using one tenth of a spool consumes one tenth of its priced filament. It does not automatically cost one complete spool. The 3D printing cost calculator follows consumption, even when the entered mass exceeds a single spool.
Use net filament mass for the spool comparison. The weight of an empty reel is not usable filament. The filament and spool calculator can separately check how much remains before starting a job.
Keep the slicer inputs with the estimate
Record the profile and filament mass used by the slicer. Supports, a brim, purge material and other generated features can change consumption. Use the estimate corresponding to the job you intend to print rather than an old model-only figure.
A 100 g job from a 1000 g spool costing 25 USD has a 2.50 USD material consumption cost. A 1200 g job at the same unit price would consume 30 USD of filament; whole-spool buying is a separate question.
Enter average power rather than the nameplate maximum
Energy cost depends on average draw over the modeled duration. Two and a half hours at 200 W is 0.5 kWh. At 0.30 USD/kWh the charge is 0.15 USD. Warm-up, enclosure conditions and material settings can affect an actual measurement, so keep the basis with the report.
Avoid double-counting a machine rate
An hourly machine rate may represent wear, maintenance or a broader internal allowance. Define what your rate includes. If it already includes electricity, adding electricity again overstates those categories.
The result is an included-cost estimate, not automatically an appropriate selling price. Evaluate labor, failed-print exposure, finishing and selling costs separately. A margin and markup calculation can help distinguish price arithmetic after a defensible cost basis is established.