Convert Femtometer (fm) to Centiinch (cin) instantly.
About these units
Femtometer (fm)
A femtometer, equal to 10⁻¹⁵ meters, is the scale at which the structure of atomic nuclei becomes measurable. Also known historically as a "fermi," this unit is used extensively in nuclear physics to describe the radii of protons, neutrons, and nuclei, which typically span 1–10 femtometers. At this scale, the strong nuclear force dominates interactions, and classical intuition breaks down almost entirely—quantum mechanics provides the only meaningful framework. The femtometer also plays a role in high-energy particle experiments, where the wavelengths of probing particles (like high-velocity electrons) may be expressed in femtometer increments. These small wavelengths allow researchers to resolve sub-nuclear structures. While invisible to any optical instrument, distances in the femtometer range can be inferred through scattering experiments, such as those performed in particle accelerators.
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.