About the Snell's Law Calculator
Angle of refraction when light passes between two media, with total internal reflection detection.
Also known as: refraction calculator, angle of refraction, law of refraction.
How to use this calculator
- Enter refractive index 1, angle of incidence, refractive index 2.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
n₁ sin θ₁ = n₂ sin θ₂
Worked example
Using the values pre-filled in the calculator above:
- Refractive index 1 = 1
- Angle of incidence = 40 °
- Refractive index 2 = 1.5
the calculator returns:
- Angle of refraction: 25.374 °
- Bending: Towards the normal (into denser medium)
- Critical angle: None — light bends away only into a denser medium