SpoolBasisHow to calculate filament cost per print
A spool of filament is priced by its net weight. A $24, 1,000 g spool works out to $0.024 per gram. A batch of three 35 g parts with another 20 g of purge uses 125 g and costs $3.00 in filament.
Filament cost = (grams per item × items + job waste) × (spool price ÷ spool grams)
Compare spools with different weights
| Spool | Sticker price | Price per kg | Cost for 125 g |
|---|---|---|---|
| 1,000 g | $24.00 | $24.00 | $3.00 |
| 750 g | $21.00 | $28.00 | $3.50 |
| 250 g | $12.00 | $48.00 | $6.00 |
To compare two products, use the price per kilogram. To check stock, subtract the amount of usable material you already have, divide the shortage by the net weight per new spool, and round up.
Common questions
Do supports and prime towers count?
Yes. If the slicer includes them in its total, use that total once. If it reports them separately, add those grams as waste.
How do I weigh a partly used spool?
Weigh the spool and subtract the weight of an identical empty reel. Use the remainder as stock. Keep a buffer if your job needs an uninterrupted run or your reel weight is uncertain.
How do I estimate a multi-color print?
Run the estimate separately for each color and add the material costs. Compare each color’s usage against the stock of that color, since one spool can’t cover a shortage in another.
For electricity, wear, or labor, continue with the full 3D printing cost calculator.