Critical Angle Calculator
Free calculate critical angle for total internal reflection from refractive indices of two media. Get instant, accurate results with our easy-to-use calculator.
Input Parameters
Medium where light originates (e.g., glass: 1.5)
Medium where light would exit (e.g., air: 1.0)
Results
Enter refractive indices to calculate
Critical Angle Formula
Formula
θc = arcsin(n₂ / n₁)
Where n₁ > n₂ for total internal reflection
Key Points
- • Occurs when n₁ > n₂
- • Light is completely reflected
- • Used in fiber optics
- • Angle measured from normal