💵 Filament Cost Calculator
Calculate the material cost of a single print based on your spool's price and weight.
Cost per gram, then cost per print
The calculator never looks at your model. It reduces the spool to a unit price and multiplies by the grams the print consumes:
cost per gram = spool cost / spool weight
material cost = grams needed × cost per gramThe defaults are a 1000 g spool at $20, so a gram costs exactly $0.02 and a 62 g print costs $1.24. Cost per gram is shown to four decimals because those digits are what separate one spool from another: $24 / 1000 g is $0.0240 a gram and pushes the same print to $1.49.
Getting the two spool numbers right
- Spool weight is the filament only. A "1 kg spool" means 1000 g of plastic; the reel adds another 150-250 g. Weigh a part-used spool and subtract the empty reel weight printed on its side.
- Grams needed comes from your slicer. Cura, PrusaSlicer and Bambu Studio all report filament in grams and metres after slicing, and the gram figure already accounts for the material's density.
- Skirt, brim and supports count. The slicer total includes them, and on a support-heavy model they can be a third of the mass.
Frequently asked questions
How much does one 3D print cost in filament?
Divide the spool price by its filament weight, then multiply by the grams your slicer reports. A $20 kilo spool works out at $0.02 a gram, so a 62 g print costs $1.24 and a 300 g print costs $6.
How many metres of filament are in a 1 kg spool?
About 335 m of 1.75 mm PLA. The strand's cross-section is pi times 0.0875 squared, or 0.02405 sq cm, and 1000 g of PLA at 1.24 g per cubic cm is 806 cubic cm, which divides out to 33,500 cm. PETG at 1.27 gives about 327 m and ABS at 1.04 about 400 m.
Does this include electricity and printer wear?
No, material only. A 10-hour print on a 120 W machine draws about 1.2 kWh, well under a dollar in most places.