How to use the critical angle and total internal reflection calculator
Find the critical angle for light going from a dense to a less dense medium. Enter denser medium index, less dense medium index in the fields above; the critical angle is computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- n1 — Denser medium index
- n2 — Less dense medium index
Worked example
With denser medium index = Crown glass, less dense medium index = Air, the calculator gives critical angle ≈ 41.81031 °.
Frequently asked questions
What is the formula for the critical angle and total internal reflection calculation?
Critical angle (°) = asin(n2 / n1). Here n1 is denser medium index, n2 is less dense medium index.
What inputs do I need for the critical angle and total internal reflection calculator?
You need denser medium index, less dense medium index. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.