Density is the one material property that touches every calculation on this site: it converts the volume a slicer knows into the mass a spool is sold by.
| Family | Material | g/cm³ |
|---|---|---|
| Engineering | Polypropylene | 0.89–0.92 |
| Nylon | PA12 | 1.00–1.04 |
| ABS/ASA | ABS | 1.02–1.08 |
| ABS/ASA | ASA | 1.05–1.10 |
| Nylon | PA6 | 1.12–1.15 |
| Flexible | TPU 95A | 1.15–1.24 |
| PLA | PLA | 1.17–1.26 |
| Engineering | Polycarbonate | 1.18–1.22 |
| PLA | Matte PLA | 1.22–1.35 |
| PETG | PETG | 1.23–1.29 |
| Composite | PETG-CF | 1.24–1.32 |
| Engineering | ULTEM 9085 | 1.29–1.34 |
| PETG | PET | 1.32–1.40 |
| PLA | Glow-in-the-dark PLA | 1.22–1.40 |
| Composite | Metal-filled PLA | 2.0–4.0 |
Why every entry is a range
Because real spools vary, and averaging that away produces a calculator that looks authoritative while quietly assuming one brand's product.
Pigment load moves base polymers by a few percent. Fillers move them enormously — the mineral in a matte PLA, the metal powder in a "bronze" filament, the chopped fibre in a composite. Two spools labelled PLA can sit at 1.17 and 1.35, which is a thirteen percent difference in how much object a kilogram will build.
Which value to use
- A single job you care about: measure it. Cut a metre, weigh it, divide by the cross-sectional area of the diameter. That is the density of the exact spool in front of you.
- Planning and estimating: the middle of the range for the polymer.
- Deciding whether a spool will finish: the top of the range. It is the pessimistic direction, and running out mid-print is the expensive error.
Where a wrong density does damage
In the filament profile. The slicer computes extruded volume from the toolpath and multiplies by whatever density you gave it, so an untouched 1.24 with a matte PLA loaded understates the mass of every part by 8.1%.
Nothing about the print looks wrong. The estimates are simply, consistently, invisibly low — which is the class of error that only surfaces when a spool runs out earlier than the arithmetic said it would.
Enter a density and diameter in the length and weight converter, or read the full property set for a material on the materials index.