Cost of a 500 g print from a $35 spool
Quick answer
A 500 gram print costs $17.50 in filament from a $35 one kilogram spool, whatever the material, because you are charged by mass. One spool yields about 2 prints of that size.
Material densities are published properties, so the volume figures are exact rather than estimated.
| Material | Mass | Volume | Filament cost | Prints per 1 kg spool |
|---|---|---|---|---|
| PLA | 500 g | 403.2 cm3 | $17.50 | 2 |
| PETG | 500 g | 393.7 cm3 | $17.50 | 2 |
| ABS | 500 g | 480.8 cm3 | $17.50 | 2 |
Why the material does not change the cost
Filament is sold by mass, so 500 grams of PLA and 500 grams of ABS cost exactly the same from a spool at the same price. What changes between materials is the volume that mass occupies, because their densities differ. ABS is the lightest of the common materials at 1.04 g/cm3, so 500 grams of it fills 480.8 cm3, while the same mass of PETG at 1.27 g/cm3 occupies only 393.7 cm3.
That matters when your slicer reports volume rather than weight, which many do. Multiply the volume in cubic centimetres by the density to get grams, then work from there. It also means a part designed to a fixed size costs slightly more in PETG than in ABS, since the denser material puts more mass into the same shape.
What this figure leaves out
The $17.50 above is the material in the finished part and nothing else. Purge, priming lines and skirts add a few percent on a single colour print and far more on a multi colour one, where the purge tower can genuinely outweigh the part. Failed prints are the larger omission: at a ten percent failure rate your real cost per good part is about $19.44.
Electricity is usually negligible for a single print, on the order of a few cents. It only becomes visible when you run several machines continuously, which is a different calculation entirely.
Filament, sorted by price per kilogram
- ELEGOO
ELEGOO ABS 3D Printer Filament 1.75mm Black 1KG Strong Layer Adhesion
$16.99 Check pricePrices change often - Polymaker
Polymaker ABS Filament Black 1KG 1.75mm, Heat Resistant, Strength
$17.10 Check pricePrices change often
Common questions
How much filament is a 500 gram print?
It is 50 percent of a standard one kilogram spool, so you get roughly 2 prints of that size from a full spool before it runs out. In length terms on 1.75 mm PLA it is about 167.8 metres, since one metre of that filament weighs close to 2.98 grams.
Does a cheaper spool always mean cheaper prints?
Per gram it does, but only if the filament actually prints. A spool that arrives wet, snaps in the feed path or jams the extruder costs far more in failed prints and wasted time than the few dollars it saved. Price per kilogram is the right way to compare like with like, and then weigh that against how consistently the brand performs.
How do I compare a multipack against a single spool?
Convert both to a price per kilogram before comparing anything. A four kilogram box at $41 is about $10.25 per kilogram, which is considerably cheaper than a single one kilogram spool at $16, but the sticker price makes it look more expensive. This is the most common pricing mistake in filament buying.
Should I reduce infill to save money?
It is the largest lever you control, and on a chunky part the saving is real. Dropping from 20 percent to 10 percent infill can cut filament use by around a quarter on a solid model, with little effect on stiffness for parts that are not load bearing. Re-slice and read the new volume rather than guessing at the saving.