Fiber Volume Fraction Calculator

What is Fiber Volume Fraction (Vf)?

Fiber volume fraction (Vf) expresses the percentage of fiber volume in a composite material. It is one of the most critical parameters because it directly influences stiffness, strength, thermal properties, and overall performance of carbon, glass, aramid or natural fiber composites.

Calculation Formula (Rule of Mixtures – Weight to Volume)

Where:
• Wf = fiber weight fraction (0–1)
• Wm = matrix weight fraction = 1 – Wf
• ρf = fiber density (g/cm³)
• ρm = matrix density (g/cm³)

Enter Values

Fiber Weight Fraction Wf (0–1) Fiber Density ρf (g/cm³) Matrix Density ρm (g/cm³) Calculate Vf

Typical Real-World Example

Carbon fiber prepreg: Wf = 0.65, ρf = 1.79 g/cm³, epoxy ρm = 1.25 g/cm³ → Vf ≈ 0.576 (57.6%). This is a common range for high-performance aerospace laminates.

Applications in Engineering

• Prepreg specification and incoming material inspection
• Mechanical property prediction (modulus, strength)
• Void content and manufacturing quality assessment
• Weight and cost optimization in aerospace, automotive & wind energy