---
title: "Aramid fibre (Kevlar) — density, melting point and properties"
description: "Aramid fibre (Kevlar) has a density of 1,440 kg/m³. Melting point, strength, conductivity, what it is used for, and whether it floats, rusts or is magnetic."
url: https://atoneplace.net/material/aramid/
site: "At One Place"
---

# Aramid fibre (Kevlar)

**Density of aramid fibre (Kevlar): 1,440 kg/m³**

1.44 g/cm³ · 89.9 lb/ft³

At 3000-3600 MPa it is stronger in tension than all but the very best steel wire, at a fifth of the density — and tension is the only direction it is strong. An aramid fibre has almost no compressive strength, so a Kevlar laminate that stops a bullet folds easily under a bending load and is usually paired with carbon fibre for that reason. It does not melt; it decomposes above about 450 °C, which is why it survives brake temperatures. The modulus quoted here is the high-modulus Kevlar 49 type; the tougher Kevlar 29 used in armour is nearer 70 GPa, and both have a slightly negative axial expansion, contracting as they warm.

## Properties

- **Density:** 1,440 kg/m³ — 1.44 g/cm³
- **Tensile strength:** 3000–3600 MPa
- **Young's modulus:** 112 GPa
- **Floats in water:** No
- **Magnetic:** No

## What it is used for

- Body armour and stab vests
- Cut-resistant gloves and sleeves
- Composite reinforcement in canoes and drone frames
- Brake pads and clutch facings

## How it compares

*Water is 1,000 kg/m³. Anything with a shorter bar than water floats in it.*

- air: 1.2 kg/m³
- expanded polystyrene foam: 20 kg/m³
- rigid polyurethane foam: 40 kg/m³
- Water — the float line: 1,000 kg/m³
- aramid fibre (Kevlar): 1,440 kg/m³
- tungsten: 19,250 kg/m³
- gold: 19,300 kg/m³
- platinum: 21,450 kg/m³

*Water is 1,000 kg/m³. Anything below that floats.*

| Material | Density | Relative to water |
| --- | --- | --- |
| rigid polyurethane foam | 40 kg/m³ | 0.04× |
| expanded polystyrene foam | 20 kg/m³ | 0.02× |
| air | 1.2 kg/m³ | 0.00× |
| aramid fibre (Kevlar) ← | 1,440 kg/m³ | 1.44× |
| platinum | 21,450 kg/m³ | 21.45× |
| gold | 19,300 kg/m³ | 19.30× |
| tungsten | 19,250 kg/m³ | 19.25× |

## Does it rust?

Aramid fibre (Kevlar) contains no iron, so it cannot rust. Whether it degrades depends on the material, not on oxidation.

## Is it magnetic?

Aramid fibre (Kevlar) is not a metal and has no ferromagnetic response.

## Common questions

### What is the density of aramid fibre (Kevlar)?

1,440 kg/m³, or 1.44 g/cm³.

### Does aramid fibre (Kevlar) float?

No. At 1,440 kg/m³ it is denser than water.

### Is aramid fibre (Kevlar) magnetic?

Aramid fibre (Kevlar) is not a metal and has no ferromagnetic response.

## Related pages

- [Does aramid fibre (Kevlar) float?](https://atoneplace.net/does-it-float/aramid/)
- [PLA](https://atoneplace.net/material/pla/)
- [ABS](https://atoneplace.net/material/abs/)
- [Acrylic (PMMA)](https://atoneplace.net/material/acrylic/)
- [Polycarbonate](https://atoneplace.net/material/polycarbonate/)
- [Polypropylene](https://atoneplace.net/material/polypropylene/)
- [PTFE](https://atoneplace.net/material/ptfe/)
- [Rigid PVC](https://atoneplace.net/material/pvc-rigid/)
- [HDPE](https://atoneplace.net/material/hdpe/)

## Sources

- Typical range compiled from manufacturer specifications — At One Place (/about/)