What the Compton wavelength is
The Compton wavelength is a quantum-mechanical property of a particle related to its mass, marking the length scale at which quantum field effects (like pair production) become important for that particle.
The formula
The Compton wavelength is λ = h / (m × c), where h is Planck’s constant, m is the particle’s rest mass, and c is the speed of light. Lighter particles have longer Compton wavelengths; for example, the electron’s is about 2.426 picometers, much larger than the proton’s due to its far smaller mass.
This calculator is for general physics education and reference.
Last reviewed August 2026