Convert Electron Radius (re) to Fingerbreadth (fingerbreadth) instantly.
About these units
Electron Radius (re)
The classical electron radius, approximately 2.818 × 10⁻¹⁵ meters, is a theoretical value derived from classical electromagnetic theory rather than an actual measured size. It represents the radius a charged sphere would need to have in order for its electrostatic self-energy to equal the electron's rest energy. Although electrons are now understood to be point-like or extremely small compared to this radius, the classical electron radius remains useful in scattering theory, especially in calculations involving Thomson scattering — the elastic scattering of electromagnetic radiation by free electrons. Thus, while not a physical dimension of the electron, the classical radius serves as a meaningful parameter in specific areas of physics and retains importance in radiation modeling and plasma physics.
Fingerbreadth (fingerbreadth)
The fingerbreadth, approximately 1.9–2 cm, is the width of an average adult finger and represents one of the smallest practical body-based units. It was historically used for fine measurement in weaving, tailoring, and small-scale construction, complementing units like cubits and handbreadths. Its human-scale precision made it intuitive, particularly in societies without standardized rulers or measuring rods. Fingerbreadths continue to be referenced in scholarly studies of ancient measurements, providing insight into the practical and anthropometric foundations of early systems.