Enter the angle of incidence and the angle of refraction into the calculator to determine the angle of deviation.

Angle Of Deviation Calculator

Refraction (Interface)
Prism (General)
Prism (Minimum Deviation)

Enter incidence angle and media to get refraction and deviation.


Related Calculators

Angle of Deviation Formula

The following formula is used to calculate the angle of deviation for a given angle of incidence and angle of refraction.

D = I - R

Variables:

  • D is the angle of deviation
  • I is the angle of incidence
  • R is the angle of refraction

To calculate the angle of deviation, subtract the angle of refraction from the angle of incidence.

What is the Angle of Deviation?

The angle of deviation is the angle between the direction of the incident ray and the direction of the refracted ray. It is a measure of how much a light ray bends as it passes from one medium to another. This bending occurs due to the change in speed of light as it moves between materials with different refractive indices. The angle of deviation is an important concept in optics and is used in the design of lenses, prisms, and other optical devices.

How to Calculate Angle of Deviation?

The following steps outline how to calculate the Angle of Deviation.


  1. First, determine the angle of incidence (I).
  2. Next, determine the angle of refraction (R).
  3. Finally, calculate the angle of deviation using the formula D = I - R.
  4. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Angle of Incidence (I) = 45°

Angle of Refraction (R) = 30°