Angle of Refraction Calculator
Calculate θ₂ from n₁, n₂, and θ₁ using Snell's law
How to Use This Calculator
- Enter the refractive indices of both media (n₁ and n₂). Common values: air ≈ 1.0, water ≈ 1.33, glass ≈ 1.5.
- Enter the angle of incidence θ₁ in degrees (measured from the normal).
- Click Calculate to obtain the angle of refraction θ₂. If total internal reflection occurs, you will be notified.
Formula
n₁sin(θ₁) = n₂sin(θ₂)
θ₂ = arcsin((n₁sin(θ₁))/n₂)
Angles are measured from the normal (perpendicular to the interface). When light enters a denser medium (higher n), it bends toward the normal; otherwise, it bends away.
Frequently Asked Questions
What is total internal reflection?
When light travels from a higher-index medium to a lower-index medium and the incidence angle exceeds the critical angle, refraction is impossible and all light reflects back.
Does wavelength matter?
Yes. Refractive index depends on wavelength (dispersion). The calculator assumes a single wavelength context.