Science Calculators

Snell's Law Calculator

Enter two materials' refractive indices and an angle of incidence to calculate the refraction angle.

32.12° refraction angle

Uses Snell's law: n1 sin(θ1) = n2 sin(θ2). Angles are measured from the normal (perpendicular to the surface), not from the surface itself.

How to use this tool

  1. 1Choose the material light is coming from.
  2. 2Choose the material light is entering.
  3. 3Enter the angle of incidence.
  4. 4See the refraction angle.

Frequently asked questions

What is total internal reflection?+

When light tries to pass into a less-dense material at too steep an angle, no refraction is mathematically possible and the light fully reflects instead — this tool flags that case explicitly.