What does this calculator do?
Compare spool price using net filament mass rather than loaded spool or shipping weight.
How to use the calculator
- Record the spool purchase basis and its original net usable fill.
- Choose model-only mass or complete job mass and name that boundary.
- Compare the displayed price per gram before comparing job material cost.
- Transfer the estimate once into the wider production-cost workflow.
How the calculation works
price / mass; cost = grams × unit price
Price per gram = spool price / original usable net grams. Job material cost = consumed grams × price per gram.
Practical calculation example
A 25-price spool with 1000 g net fill costs 0.025 per gram. A 100 g complete job costs 2.50 in filament.
Understanding the results
Include supports, purge and failed parts; cheaper material may have higher cost per accepted part if it creates rejects.
Price the material you actually consume
Filament cost is a material-only estimate. It multiplies the consumed mass by the price per usable gram from the purchased spool. The result does not include electricity, machine occupation, support removal, shipping to a customer or profit. Its value is a transparent baseline: you can compare two spools or see the material effect of a slicing change without mixing it with unrelated expenses. Decide whether your mass input describes only the model or the complete sliced job, including supports and purge. Both are valid questions, but their results should not be compared as if they had the same boundary.
Use net fill rather than gross package weight
The spool-mass denominator is the usable filament, not filament plus plastic reel and cardboard packaging. A spool with a labeled one-kilogram net fill supplies 1,000 g for this equation, even if the delivered package weighs more. For a partially used spool, purchase price divided by the original net fill gives its material unit cost; entering the remaining mass as the original purchase quantity would artificially make every remaining gram more expensive. Separately calculate how much material remains when deciding whether a job can finish. Inventory availability and original cost per gram answer different questions.
Reproduce and compare the calculation
A spool priced at 25 with 1,000 g usable fill costs 0.025 per gram. A 100 g job therefore consumes material worth 2.50. Another spool priced at 18 with 750 g fill costs 0.024 per gram, so the same 100 g costs 2.40. The cheaper package price does not by itself establish the cheaper unit material price. Conversely, a premium spool at 40 per kilogram raises this job's material estimate to 4.00. Use one currency throughout; the display selector does not perform an exchange-rate conversion between suppliers.
Translate slicing changes into an actual saving
If a revised orientation reduces the complete sliced mass from 100 g to 80 g at 0.025 per gram, the material saving is 0.50. That saving may be outweighed by additional sanding, a longer print or a higher rejection rate, so use the general print-cost calculator before claiming lower delivered cost. Slicer mass depends on its material-density assumption. Compare a representative printed job with a scale measurement if estimates regularly disagree. A profile with the wrong density can report a plausible-looking mass while its volume estimate remains unchanged, producing a systematic cost error.
Choose what is included in purchase price
Use a documented purchase basis for consistent comparisons. A shipping charge shared among several spools can be allocated proportionally or kept as a separate procurement expense. Taxes or discounts should be treated according to the actual context rather than silently mixed across inputs. For a multi-material job, a single average price may hide important differences between support and model materials; calculate each material's mass and cost separately or use the dedicated multi-material tool. Keep unusual losses separate if they are not represented in the declared mass. The result is only as complete as the amount of consumed material you choose to include.
Advanced tips
- Compare supplier offers by cost per usable gram.
- Verify slicer density when measured consumption differs systematically.
Common mistakes
- Including the empty reel in usable mass.
- Using current remaining mass as the original paid spool fill.
- Calling a material saving a complete production saving.
Frequently asked questions
Does this include the supports?
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Only when your entered mass includes them. Check the slicer breakdown and avoid adding them twice.
Can I price a partly used spool?
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Yes. Keep the original price and net purchased mass for unit cost; use remaining-material tools separately for stock availability.
Sources & methodology
Mathematical results depend on the supplied inputs. Material properties and machine limits need confirmation for your exact equipment.