What do T300, T700, and T800 mean in carbon fiber materials?

author: Lily

2025-10-15

To put it simply, it can be understood like this:
1. "T" stands for tensile strength. The following number, such as 300, 700, or 800, roughly corresponds to the tensile strength of the carbon fiber, measured in kgf/mm² (kilogram-force per square millimeter). A higher number generally indicates higher fiber strength and performance.
2. Due to Toray's leadership in the global carbon fiber industry, these designations have become common industry jargon. Even other companies (such as Hexcel in the United States and SGL in Germany) that produce products with similar performance often use these designations to compare and describe their products.

Below is a detailed performance comparison table and explanation:

T300: This is a standard modulus carbon fiber and was widely used in the early days.
T700: This is a high-strength, medium-modulus carbon fiber, offering a good balance between strength and cost. It is currently the most widely used type.
T800: This is a higher-strength carbon fiber with excellent performance, but generally comes at a higher cost.

Generally speaking, the larger the number, the higher the tensile strength of the carbon fiber.

Features/Parameters	T300	T700	T800	T1000
Tensile Strength	Lower (e.g. ~3.5 GPa)	Higher (e.g. ~4.9 GPa)	Higher (e.g. ~5.5 GPa)	Very high (e.g. > 6.4 GPa) / high strength but also high modulus
Tensile modulus	Lower (e.g. ~230 GPa)	Higher (e.g. ~230 GPa)	Higher (e.g. ~290 GPa)	Very high (e.g. > 300 GPa) / modulus even higher
Elongation at break	Relatively high (e.g. ~1.5%)	Relatively high (e.g. ~1.7%)	Relatively low (e.g. ~1.8%)	Lower (e.g. < 1.7%) / Likely lower
Cost	Relatively low	Medium	Higher	Very high
Density	Relatively stable, with little difference between different brands	Relatively stable	Relatively stable	Relatively stable
Application	Sporting goods, general industrial parts, etc.	Aerospace, automobiles, high-end sporting goods, etc.	Aerospace, racing, etc.	Aerospace, satellites, precision instruments, etc.

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