Refractive Index Calculator

Snell's Law & Critical Angle

Calculate refraction angles using Snell's law and find critical angles for total internal reflection.

Refraction Parameters

°

Formula

n₁ sin(θ₁) = n₂ sin(θ₂)

Note

Total internal reflection occurs when the calculated angle would exceed 90°.

Common Media

Vacuum:1.0
Air:1.000293
Water:1.333
Glass:1.52
Diamond:2.417
Ice:1.31

Snell's Law

Snell's law describes how light bends when passing between different media. The relationship is: n₁ sin(θ₁) = n₂ sin(θ₂)

  • Light bends toward normal when entering denser medium
  • Light bends away from normal when entering less dense medium

Total Internal Reflection

When light travels from a denser to less dense medium at angles greater than the critical angle, it reflects completely back into the denser medium.

  • Fiber optic cables
  • Prisms and diamonds
  • Mirages