Refractive index to percent of light speed
Type a value in n to get it in % instantly.
66.67%
That's 1.13× as dense as water, while window glass is 1.01× higher. Light travels 1.5 times slower inside it.
What it means
How much does it bend light?
Index depends on wavelength — that is what makes a prism work. Published values are usually for the yellow sodium line at 589 nm.
The math
How to convert n to %
From the index: the speed inside is c ÷ n, the critical angle is arcsin(1 ÷ n), Brewster’s angle is arctan(n), and the head-on reflectance is ((n − 1) ÷ (n + 1))².
Example: 1.5 n = 66.6667 %.
Every unit
Your index in every unit
Tables
n to % conversion table
| n | % |
|---|---|
| 1.0003 n | 99.97 % |
| 1.2 n | 83.3333 % |
| 1.31 n | 76.3359 % |
| 1.33 n | 75.188 % |
| 1.46 n | 68.4932 % |
| 1.5 n | 66.6667 % |
| 1.6 n | 62.5 % |
| 1.77 n | 56.4972 % |
| 2 n | 50 % |
| 2.42 n | 41.3223 % |
| 3.4 n | 29.4118 % |
% to n conversion table
| % | n |
|---|---|
| 29.4 % | 3.40136 n |
| 41.3 % | 2.42131 n |
| 50 % | 2 n |
| 56.5 % | 1.76991 n |
| 62.5 % | 1.6 n |
| 66.7 % | 1.49925 n |
| 68.5 % | 1.45985 n |
| 75.2 % | 1.32979 n |
| 76.3 % | 1.31062 n |
| 83.3 % | 1.20048 n |
| 100 % | 1 n |
Quick answers
Quick answers
- How many % is 1 n?
- 1 n is 100 %.
- How many % is 10 n?
- 10 n is 10 %.
- How many % is 1.5 n?
- 1.5 n is 66.6667 %.
The units
About these units
Refractive index (n)
How many times slower light travels in the material.
Percent of light speed (%)
What fraction of the vacuum speed light manages.
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