What the de Broglie wavelength is
In 1924, Louis de Broglie proposed that every moving particle has an associated wavelength, not just light. This wave-particle duality is a cornerstone of quantum mechanics and becomes noticeable at very small masses, like electrons, and negligible at everyday, macroscopic scales.
The formula
The de Broglie wavelength is calculated as λ = h / p = h / (m × v), where h is Planck’s constant (6.62607015 × 10⁻³⁴ J·s), m is the particle’s mass in kilograms, and v is its velocity in meters per second. The default values in this calculator represent an electron moving at 2,000,000 m/s, a typical scenario in electron microscopy and physics problem sets.
This formula is non-relativistic and works well for speeds well below the speed of light. This tool is for general educational and study purposes.