Convert Earth's Equatorial Radius (R⊕) to Centiinch (cin) instantly.
About these units
Earth's Equatorial Radius (R⊕)
The Earth's equatorial radius is approximately 6,378.1 km. This distance represents the radius measured along the equator, where Earth's rotational bulge makes it slightly larger than the polar radius. Geodesists, cartographers, and astronomers use the equatorial radius for mapping, satellite positioning, and calculating gravitational effects. It is fundamental to defining the shape of the Earth as an oblate spheroid rather than a perfect sphere. Precise knowledge of R⊕ enables accurate navigation, climate modeling, and orbital calculations, forming the basis for modern geodesy and Earth observation systems.
Centiinch (cin)
A centiinch is 1/100 of an inch, making it a small but straightforward derivative of the imperial system. Although seldom used today, it historically appeared in precision engineering, machining, and scientific instruments that relied on extremely fine calibrations before widespread adoption of decimal-based units like millimeters. Because the inch was long established in many English-speaking industries, dividing it into 100 equal parts provided a convenient decimal alternative to the more cumbersome 1/8 or 1/16 subdivisions found in carpentry and early tooling. The centiinch never gained strong traction, particularly once the metric system became dominant for precision work. However, it remains an interesting footnote in the evolution of measurement, illustrating attempts to reconcile the decimal preference with traditional imperial standards.