Petameter to Electron Radius (Classical)

The classical electron radius is a theoretical length scale derived from the electron's charge and mass, approximately 2.818 × 10⁻¹⁵ meters.

re = e²/(4πε₀mec²) ≈ 2.8179 × 10⁻¹⁵ m, where e is electron charge and me is electron mass.

To convert to meters: multiply by 2.8179403262 × 10⁻¹⁵.

Used in calculating X-ray and gamma-ray scattering probabilities off electrons (Thomson and Compton scattering).

Despite its name, the electron is a point particle in quantum theory — the 'classical radius' is a theoretical construct, not the electron's actual size.

Assuming this is the actual physical size of the electron — quantum mechanics shows the electron has no measurable size.

Think of it as the scale at which classical electromagnetic self-energy equals the electron's mass-energy.