Density

Density tells you how heavy a material is for its size. Learn how it affects part weight and filament length, and how to read it.

3 min read · Updated October 11, 2026 · Numbers update live from our materials database.

What it means in practice

Density is mass per unit volume. It looks like a dull number, but it shapes several everyday decisions:

Key takeaways

Density is mass per unit volume; it sets part weight and how far a spool goes.
Water is 1.00 g/cm³, so solid material below that floats.
Datasheet density is for solid material; printed parts with infill weigh less.
Fillers such as glass fibre and metal raise density; most polymers sit in a narrow band.

Filaments1.23 g/cm³typical · range 0.81–7.85 · 261 materials

Resins1.18 g/cm³typical · range 1.01–1.73 · 73 materials

Powders1.07 g/cm³typical · range 0.87–1.3 · 20 materials

Pellets1.29 g/cm³typical · range 0.9–1.5 · 30 materials

Part weight. For the same design, a denser material gives a heavier part. That matters for drones, wearables, robot arms and anything handheld.
Value per spool. Filament is sold by weight. A lower-density filament gives more metres per kilo, and so more parts.
Floating. Water is 1.00 g/cm³. Solid material below that floats, which is useful for marine and fishing parts.
Stiffness and strength for weight. Dividing modulus or strength by density lets you compare materials for lightweight parts.

Tip

For lightweight parts, divide modulus or strength by density. That ranks materials by stiffness or strength for their weight.

The usual method weighs a sample in air and again in water. The difference gives its volume, and so its density. This is the Archimedes principle.

Standards: ISO 1183 and ASTM D792.
Units: g/cm³, which is the same as g/mL. Some sheets use kg/m³ (multiply g/cm³ by 1,000).

Material vs printed part. The datasheet value is for solid material. A printed part with infill and small voids weighs less than volume × density. Slicer weight estimates account for infill.
Liquid vs cured resin. Resins shrink as they cure, so cured density is usually higher than liquid density. Check which one the sheet gives.
Fillers. Glass fibre, minerals and metal powders raise density. Carbon fibre raises it only a little.
Foaming filaments. Some lightweight filaments expand as they print. The printed density then depends on the print temperature, not just the material.
Metal parts. For metal FFF, the useful value is the density after sintering, compared with the fully dense metal.
Crystallinity. Semi-crystalline plastics get slightly denser as they crystallise, so annealed parts may differ a little.

All materials: 0.81–7.85 g/cm³ (median 1.2 g/cm³, 384 materials)
Resins: 1.01–1.73 g/cm³ (median 1.18 g/cm³, 73 materials)
Powders (SLS and MJF): 0.87–1.3 g/cm³ (median 1.07 g/cm³, 20 materials)
Engineering materials: 0.81–1.73 g/cm³ (median 1.18 g/cm³, 182 materials)
Glass-fibre filled: 0.95–1.51 g/cm³ (median 1.31 g/cm³, 35 materials)

Good to know

Metals stretch the top of the overall range. Most polymers sit in a narrow band.

Density of common filaments (g/cm³)

Bar = lowest to highest, dot = median. 138 materials, live from our database.

Material	Polymer	Density
3DXTECH HyperLite PP	PP	0.81 g/cm³
HP 3D HR PP	PP	0.87 g/cm³
Formlabs Polypropylene Powder	PP	0.89 g/cm³
Ultrasint PP 1400 Black	PP	0.89 g/cm³
Formfutura Centaur PP Medical Grade Pellets	PP	0.9 g/cm³