Carbon fiber (AS4) vs S-2 glass fiber

Every value below is a typical room-temperature figure with its source, test method and conditions — the same dataset that drives the calculators.

Carbon fiber (AS4) in fullS-2 glass fiber in full← All materials
PropertyCarbon fiber (AS4)S-2 glass fiberDifference
Density1.79 g/cm³2.46 g/cm³S-2 glass fiber — 37% higher
Young's modulus E231 GPa86.9 GPaCarbon fiber (AS4) — 2.7× higher
Tensile strength4447 MPa4890 MPaS-2 glass fiber — 10% higher
  • Hexcel HexTow carbon fiber product datasheet
  • AGY S-2 Glass product datasheet

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.