Convert Electron Radius (re) to Point (pt) 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.
Point (pt)
A point is a typographic unit traditionally equal to 1/72 of an inch (in digital typography) or 0.352777 mm. Historically, however, the point system varied widely across regions and printing houses. In the era of metal movable type, each foundry often produced its own proprietary sizes, making typefaces and point values incompatible between printers. The modern point was standardized largely due to the demands of the publishing industry and later digital systems, especially PostScript and desktop publishing software. The point became essential because typography requires extremely fine control over letter height, line spacing, and layout—far beyond what conventional measurement systems could easily express. Designers and typesetters rely on points to specify the sizes of fonts, the spacing between lines (leading), and the thickness of rules or strokes. In digital environments, the point remains foundational even though screen resolutions vary. Software uses points as virtual units that are converted into pixels depending on display density. Thus, the point bridges the traditional world of print with modern digital rendering, maintaining continuity in the long history of written communication.