Snell's Law Calculator
Solve Snell's law for refraction angle, incident angle, refractive index, critical angle, total internal reflection and Brewster angle.
Refractive index depends on wavelength, temperature, and material composition; the selected value is a reference input.
Refraction from Snell's law
This calculator follows the English optics intent for Snell's law: solve a missing angle or refractive index and flag total internal reflection when the refracted ray cannot exist.
Angles are measured from the normal to the surface, not from the surface itself.
The critical angle applies only when light travels from higher refractive index to lower refractive index.
Brewster angle is an idealized polarization boundary result.
Refractive index caveats
Frequently Asked Questions
Sources and References
- 16.2 RefractionOpenStax
- 1.4 Total Internal ReflectionOpenStax
- Snell's Law CalculatorPearson
- Total Internal ReflectionHyperPhysics
Calculations are based on the listed reference sources. Links open in a new tab.
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