Critical Angle Calculator
🔍 Light & optics. Use the Critical angle formula to find critical angle, refractive index n: pick the value you want, type the others, and the answer updates as you go.
Critical angle41.81 °
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Critical angle | ° |
| Refractive index n | no unit |
Worked example
Find the critical angle when Refractive index n = 1.5.
Using sin c = 1/n: Critical angle = 41.81 °.
Frequently asked questions
What is the formula for Critical angle?
sin c = 1/n.
What do the letters stand for, and what units are used?
Critical angle in °, Refractive index n.
How do you calculate critical angle?
Put the values into sin c = 1/n. For example, with Refractive index n = 1.5, critical angle = 41.81 °.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (critical angle, refractive index n) and fill in the others: it rearranges the formula for you.
