These are the lightest materials in our library, ranked by density. Engineering plastics are lightest, and among metals aluminum and titanium beat steel handily.
| Material | Density (g/cc) |
|---|---|
| UHMW | 0.93 |
| HDPE | 0.95 |
| ABS | 1.05 |
| Nylon 6/6 | 1.14 |
| Polycarbonate | 1.20 |
| PEEK | 1.32 |
| PVC | 1.40 |
| Acetal (Delrin) | 1.41 |
| PTFE | 2.20 |
| Aluminum | 2.70 |
| Titanium | 4.51 |
| Steel | 7.85 |
Steel is nearly three times as dense as aluminum and about eight times as dense as the lightest plastics, which is why weight-critical designs reach for aluminum, titanium, or polymers.
FAQ
Why not just always use the lightest material? Because density alone doesn’t determine whether a part can carry a given load. A thin-walled aluminum or titanium part often ends up lighter overall than an ultralight plastic part sized to match the same stiffness or strength, since polymers typically need a much larger cross-section to match a metal’s load capacity.
See the Material Density Chart and the Density Calculator.
Density and why it matters
Density is the mass of a material for a given volume, and it is shown here in grams per cubic centimeter, where water is 1. Materials with a lower density than water, such as UHMW and HDPE, will float. Lighter materials reduce the weight of a part, which helps with handling, shipping, and moving parts.
Weight is not the whole story
A lighter material is not always the better choice, since plastics are less stiff than metals and can creep under load. Aluminum is about a third the density of steel, and titanium is in between. Compare strength to weight and stiffness to weight, as well as density, when weight matters, and check cost, machinability, and operating temperature too.