Snell's Law & Critical Angle Calculator
Angle of refraction from Snell's law, critical angle for total internal reflection, and light speed in each medium.
How to use the Snell's Law & Critical Angle Calculator
- Enter or select: Refractive index n₁, Angle of incidence θ₁, Refractive index n₂.
- The results (Angle of refraction θ₂, Critical angle, Light speed in medium 1, Light speed in medium 2, Note) are calculated instantly as you type.
- Use “Copy link” to share the calculation with the same input values.
Formula
- n₁ sin θ₁ = n₂ sin θ₂
- θc = arcsin(n₂/n₁)