Refractive Index Converter
Free Refractive index Converter for other units. Enter a value to see equivalent measurements across systems. Includes formulas and worked examples.
Formula
n1 x sin(angle1) = n2 x sin(angle2) | Critical angle = arcsin(n2/n1)
Snells law relates the incident angle and refracted angle through the refractive indices of two materials. The critical angle for total internal reflection exists only when light travels from a denser to less dense medium (n1 > n2). Light speed in a material = c / n, where c is the speed of light in vacuum.
Worked Examples
Example 1: Light Entering Water from Air
Problem: Light hits water at a 45-degree angle of incidence from air. Find the refracted angle.
Solution: n1 x sin(angle1) = n2 x sin(angle2)\n1.000293 x sin(45) = 1.333 x sin(angle2)\nsin(angle2) = (1.000293 x 0.7071) / 1.333 = 0.5306\nangle2 = arcsin(0.5306) = 32.04 degrees
Result: Refracted angle = 32.04 degrees (light bends toward normal)
Example 2: Critical Angle for Glass to Air
Problem: Find the critical angle for total internal reflection from crown glass to air.
Solution: Critical angle = arcsin(n2 / n1)\nCritical angle = arcsin(1.000293 / 1.523)\nCritical angle = arcsin(0.6568)\nCritical angle = 41.04 degrees
Result: Critical angle = 41.04 degrees; angles above this cause total internal reflection
Frequently Asked Questions
What is the refractive index?
The refractive index (n) is a dimensionless number that describes how fast light travels through a material compared to the speed of light in vacuum. It equals the ratio of the speed of light in vacuum (c = 299,792,458 m/s) to the speed of light in the material. For example, water has a refractive index of 1.333, meaning light travels 1.333 times slower in water than in vacuum. The refractive index determines how much light bends when passing between different materials, which is the basis of lenses, prisms, and fiber optics.
What formula does Refractive Index Converter use?
The formula used is described in the Formula section on this page. It is based on widely accepted standards in the relevant field. If you need a specific reference or citation, the References section provides links to authoritative sources.
Can I use the results for professional or academic purposes?
You may use the results for reference and educational purposes. For professional reports, academic papers, or critical decisions, we recommend verifying outputs against peer-reviewed sources or consulting a qualified expert in the relevant field.
Can I use Refractive Index Converter on a mobile device?
Yes. All calculators on NovaCalculator are fully responsive and work on smartphones, tablets, and desktops. The layout adapts automatically to your screen size.
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How do I get the most accurate result?
Enter values as precisely as possible using the correct units for each field. Check that you have selected the right unit (e.g. kilograms vs pounds, meters vs feet) before calculating. Rounding inputs early can reduce output precision.