What is the Brewster angle?

The Brewster angle is the angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent surface, with no reflection. It occurs when the reflected and refracted rays are perpendicular to each other.

How is the Brewster angle calculated?

The Brewster angle (θ_B) is calculated using the formula θ_B = arctan(n2 / n1), where n1 is the refractive index of the incident medium and n2 is the refractive index of the transmitted medium. This calculator uses the two indices you provide.

What are typical refractive index values?

For air, the refractive index is approximately 1.00. For glass, it's around 1.5, and for water, about 1.33. The calculator accepts any positive values, so you can use these or other known indices.

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Калькулятор: Brewster Angle.

Используйте Калькулятор: Brewster Angle, чтобы получить понятный и практичный результат по введённым данным.

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Incident-medium index

Transmitted-medium index

angleDegrees

56,30993°

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Canonical URL: https://mathify.one/ru/physics/brewster-angle

Cite as: Mathify. (n.d.). Калькулятор: Brewster Angle. https://mathify.one/ru/physics/brewster-angle

Use Cases

Optics and Lens Design

Determine the angle at which anti-reflective coatings or optical components should be oriented to minimize reflection for a given pair of media.

Example: For air (n=1.00) to glass (n=1.5), the Brewster angle is about 56.3°.

Photography and Polarizing Filters

Find the angle to set a polarizing filter to reduce glare from non-metallic surfaces like water or glass.

Example: For air to water (n=1.33), the Brewster angle is about 53.1°.

Frequently Asked Questions

What is the Brewster angle?: The Brewster angle is the angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent surface, with no reflection. It occurs when the reflected and refracted rays are perpendicular to each other.
How is the Brewster angle calculated?: The Brewster angle (θ_B) is calculated using the formula θ_B = arctan(n2 / n1), where n1 is the refractive index of the incident medium and n2 is the refractive index of the transmitted medium. This calculator uses the two indices you provide.
What are typical refractive index values?: For air, the refractive index is approximately 1.00. For glass, it's around 1.5, and for water, about 1.33. The calculator accepts any positive values, so you can use these or other known indices.

Tips & Common Mistakes

Tips

Ensure you enter the refractive indices in the correct order: incident medium first, then transmitted medium.
The Brewster angle is measured from the normal (perpendicular) to the surface, not from the surface itself.
For a given pair of media, the Brewster angle is unique and depends only on the ratio of the refractive indices.
If the incident medium has a higher index than the transmitted medium, the Brewster angle will be less than 45°.

Common Mistakes to Avoid

Swapping the incident and transmitted indices, which gives the complementary angle (90° - correct Brewster angle).
Using degrees and radians inconsistently; this calculator returns the angle in degrees.
Assuming the Brewster angle is the same for all polarizations; it only applies to light polarized parallel to the plane of incidence.

Last updated: August 13, 2026