Snells Law Calculator

Snell’s Law Formula: n1 sin θ1 = n2 sin θ2

Enter the unknown value as ‘x.’

Index of Refraction of First medium(n1):

Angle of Incidence(θ1):

Index of Refraction of Second medium(n2):

Angle of Refraction(θ2):

x =


Snell’s Law Calculator is a free online tool that displays the angle of refraction using Snell’s law. BYJU’S online Snell’s law calculator tool performs the calculation faster, and it displays the refraction angle in a fraction of seconds.

How to Use the Snell’s Law Calculator? 

The procedure to use Snell’s law calculator is as follows:

Step 1: Enter the refraction index of first and second medium, angle of incidence, and x for the unknown in the input field

Step 2: Now click the button “Calculate x” to get the result

Step 3: Finally, the angle of refraction using Snell’s law will be displayed in the output field

What is Meant by Snell’s Law?

We know that when light travels from one medium to the other medium, either it reflects or refracts. In Physics, Snell’s law describes the working mechanism of refraction. If the light ray enters into the different medium, the wavelength and the speed of the ray will change. The light ray may either bend towards the normal of two medium boundaries or away from the medium. The refraction angle depends on the refraction index of both media. Snell’s law is only applicable to the isotropic medium. Snell’s law formula is given as follows:

 n1 sin θ1 = n2 sin θ2


n1 and n2 are the refractive index of medium 1 and medium 2 respectively

θ1 is the angle of incidence

θ2 is the angle of refraction

Snell’s law formula is also expressed as 

Sin i / Sin r = μ


“i” is the angle of incidence

“r” is the angle of refraction

“ μ” is the refractive index of the second medium with respect to the first medium (constant)


Find the angle of refraction of the light beam that passes from the air to the glass. Given that the angle of incidence is 30°, the refractive index of air is 1. 000293, the refractive index of glass is 1.50.


Given: Refractive index of air (n1) = 1. 000293

Refractive index of glass (n2) = 1.50

Angle of incidence (θ1) = 30°

To find θ2:

sin(θ) = nsin(θ)/n

sin(θ) = 1.000293 x sin(30°)/1.5

sin(θ) = 0.333

θ = sin-1(0.333)

θ = 19.4°

Therefore, the angle of refraction is 19.4°

Disclaimer: This calculator development is in progress some of the inputs might not work, Sorry for the inconvenience.


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