basic

Snell's Law Refraction & Critical Angle Calculator

n₁sinθ₁ = n₂sinθ₂ — refracted angle and critical angle.

Calculates the refracted angle using Snell's Law and the critical angle for total internal reflection from the two refractive indices.

Marcus Laurent By Marcus Laurent
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

sinθ₂ = n1×sinθ₁/n2; θ_c = arcsin(n2/n1)

In depth

Calculates the refracted angle using Snell's Law and the critical angle for total internal reflection from the two refractive indices.