Bragg's Law Calculator

About this calculator

This calculator finds the diffraction angle in crystallography using Bragg's law: nλ = 2d·sinθ, where n is the diffraction order (an integer), λ is the wavelength of the incident radiation, d is the spacing between crystal lattice planes, and θ is the angle of incidence measured from the plane (not the normal). Constructive interference — a detectable diffraction peak — occurs only when this condition is satisfied.

Crystallographers and materials scientists use Bragg's law in X-ray diffraction (XRD) to determine unknown crystal structures and lattice spacings by measuring the angles at which diffraction peaks appear, a technique that was foundational to solving structures like DNA and countless minerals and materials. Enter the diffraction order, wavelength, and lattice spacing to find the angle, or solve for any of the other variables.