Quick weight estimate without a file
Densities the 3D printer filament calculator uses
Each material has a typical datasheet density. Real spools vary a little by brand and color.
| Material | g/cm³ | Material | g/cm³ |
|---|---|---|---|
| PLA | 1.24 | Standard resin (SLA) | 1.12 |
| PETG | 1.27 | Tough resin (SLA) | 1.18 |
| ABS | 1.04 | PA12 (SLS/MJF) | 1.01 |
| ASA | 1.07 | Aluminium | 2.70 |
| TPU (flexible) | 1.21 | Steel | 7.85 |
| Nylon (PA12) | 1.01 | Stainless steel 316L | 8.00 |
| Polycarbonate | 1.20 | Titanium Ti-6Al-4V | 4.43 |
| PLA-CF | 1.29 | Brass | 8.50 |
| Wood (pine) | 0.50 |
How the grams are worked out
Grams = volume in cm³ × density × % solid. The 20 mm test cube has a volume of 8 cm³. Solid, it weighs 9.92 g in PLA, 10.16 g in PETG and 8.32 g in ABS.
At 30 % solid the PLA cube drops to about 2.98 g. Treat % solid as the share of the volume that ends up as plastic, walls and top layers included. A small part with thick walls is close to solid even at low infill, so set the field higher than the infill number.
Work out the filament for your model
- Drop the STL, 3MF or STEP on the viewer, or press Open File.
- Open Info. The volume is shown in cm³, and the watertight line tells you whether to trust it.
- Pick the material and set % of solid to match your walls and infill.
- Read the weight in grams. Without a file, the form above takes a volume, a material and % solid and gives the same weight to 0.1 g.
The form starts at 25 cm³ of PLA at 30 % solid, which comes to 9.3 g.
From grams to metres of filament
Spools are sold by weight, but the slicer counts length. One cm³ of plastic is about 0.42 m of 1.75 mm filament, or about 0.16 m of 2.85 mm. The solid PLA cube above, 8 cm³, needs about 3.3 m of 1.75 mm filament.
Divide the grams by the spool weight to see how many parts one spool gives. The 9.3 g part from the form fits about 107 times on a 1 kg spool, before skirt, supports and failed prints.
| 1 kg spool | Plastic | 1.75 mm, about | 2.85 mm, about |
|---|---|---|---|
| PLA (1.24) | 806 cm³ | 335 m | 126 m |
| PETG (1.27) | 787 cm³ | 327 m | 123 m |
| ABS (1.04) | 962 cm³ | 400 m | 151 m |
These follow from the densities and the nominal diameter. Weigh a part-used spool and subtract the empty reel to know whether a long job will finish; a spool that runs out near the top of a tall print wastes every layer below.
Exact filament use from G-code
The volume estimate is for planning. Once the part is sliced, open the G-code in the G-code viewer. It reads filament length and weight from the slicer's comments and adds its own count of net extrusion, with retractions cancelling out. On 13 real files that count was within 1.1 % of PrusaSlicer's number.
This figure includes supports, skirt and brim, which the model volume leaves out. The same file gives the hours on print time.
How much the filament for one part costs
Filament cost per part = grams ÷ 1000 × your price per kg. Use the price you paid for the spool, including shipping, and the gram count from here or from G-code. To add machine hours and an hourly rate for a full quote, use the 3D print cost calculator.
The weight is worked out in your browser from the mesh, without sending the file anywhere. For overall size and area first, see STL dimensions.
Questions and answers
How much filament does a 3D printer use for one part?
Multiply the part's volume by the material density and by the share of the part that is solid. For the exact figure after slicing, open the G-code.
How do I calculate the volume of an STL file?
Open the STL in the viewer above. Info shows the volume in cm³ or in³; the mesh must be watertight for it to be right.
Why does my slicer show a different weight?
The slicer knows the real walls, infill pattern, supports and skirt. The calculator uses one % solid number for the whole part, so it is an estimate.
Can I calculate resin instead of filament?
Yes. Pick standard or tough resin in the material list; the weight uses 1.12 or 1.18 g/cm³.
Do brand and color change the weight?
Slightly. The densities in the table are typical datasheet values; a filled or colored blend can sit a little above or below them.
Does 1.75 mm or 2.85 mm filament change the weight?
No. The weight depends on volume and density only; the diameter changes how many metres that weight is. A kilogram of PLA is about 335 m at 1.75 mm and about 126 m at 2.85 mm.