Fiber comparison
E-glass fiber vs Carbon fiber (T300)
Every value below is a typical room-temperature figure with its source, test method and conditions — the same dataset that drives the calculators.
Which to choose
Carbon is roughly three times stiffer and lighter, which is the whole reason aerospace and performance sport use it; E-glass costs a small fraction as much, tolerates more strain before breaking and does not conduct electricity. Glass for cost, radomes and impact tolerance; carbon wherever stiffness per kilogram decides the design.
| Property | E-glass fiber | Carbon fiber (T300) | Difference |
|---|---|---|---|
| Density | 2.54 g/cm³ | 1.76 g/cm³ | E-glass fiber — 44% higher |
| Young's modulus E | 72.4 GPa | 230 GPa | Carbon fiber (T300) — 3.2× higher |
| Tensile strength | 3450 MPa | 3530 MPa | Carbon fiber (T300) — 2% higher |
Where these numbers come from
- Daniel & Ishai, Engineering Mechanics of Composite Materials, 2nd ed.
Typical room-temperature values for learning and preliminary design; grades vary widely and a supplier datasheet always overrides a textbook figure. Confirm against the datasheet before design work.