basic

Snell's Law Calculator

Refraction angle when a ray crosses a boundary.

Compute the angle of refraction when light passes from a medium of refractive index n₁ into a medium of refractive index n₂, and detect total internal reflection.

Daniel Oh By Daniel Oh
Reviewed by Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

°

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

n₁ · sin(θ₁) = n₂ · sin(θ₂)

In depth

Compute the angle of refraction when light passes from a medium of refractive index n₁ into a medium of refractive index n₂, and detect total internal reflection.