Snell's Law Calculator

Free online Snell's law calculator. Calculate the angle of refraction and critical angle between two mediums.

Law of Refraction Calculator

Refraction angle: 19.47°

What is Snell's Law?

Snell's law is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air.

n₁ × sin(θ₁) = n₂ × sin(θ₂)
  • n₁ & n₂: The refractive indices of the respective media. (Vacuum = 1, Air ≈ 1.0003, Water ≈ 1.333).
  • θ₁: The angle of incidence.
  • θ₂: The angle of refraction.