Enter the speed of light and the speed of light in a medium, and this calculator will determine the index of refraction. The index fraction is calculated with the formula presented below. This formula is also known as Snell’s Law.

Index of Refraction Formula

The formula for calculating a refraction index is as follows: 

 n = c / v
  • Where n is the index of refraction
  • c is the speed of light in a vacuum = 299,792.46km/s
  • v is the speed of light in a given medium

To calculate an index of refraction, divide the speed of light in a vacuum by the speed of light in the medium.

Index of Refraction Definition

An index of refraction is the ratio of the speed of light through a vacuum with respect to the speed of light through some other medium, such as water.

How to calculate index of refraction?

How to calculate index of refraction?

  1. First, determine the speed of light in a vacuum.

    The speed of light in a vacuum is known to be 299,792.46 km/s.

  2. Next, measure the speed of light in the medium.

    For example, the speed of light through water is 225,000.00 km/s.

  3. Finally, calculate the index of refraction.

    Using the formula above and values from steps 1 and 2, calculate the index of refraction.

FAQ

What is an index of refraction?

An index of refraction is the ratio of the speed of light through a vacuum with respect to the speed of light through some other medium, such as water.