What Brewster’s angle is
When unpolarized light hits a boundary between two transparent media at a specific angle, the reflected light becomes fully polarized parallel to the surface. This special angle is called Brewster’s angle, and it’s used in photography filters, laser design, and anti-glare optics.
The formula
Brewster’s angle is calculated as θB = arctan(n2 / n1), where n1 is the refractive index of the medium the light travels through initially and n2 is the refractive index of the medium being reflected off. At this angle, the reflected and refracted rays are perpendicular to each other.
This calculator is for general optics and physics education.
Last reviewed August 2026