Convert Nanometer (nm) to Femtometer (fm) instantly.
About these units
Nanometer (nm)
A nanometer—one billionth of a meter (10⁻⁹ m)—is central to nanoscience, nanotechnology, and molecular biology. Many structures essential to life fall into this scale: DNA's double helix is about 2 nm wide, viruses often measure tens to hundreds of nanometers, and key cell structures like ribosomes are on the order of 20–30 nm. In engineering, nanometers define the dimensions of modern semiconductor technology. Silicon transistors have shrunk to features only a few nanometers wide, approaching the physical limits of electron behavior in solid-state materials. In optics, wavelengths of ultraviolet light can be expressed in nanometers, as can surface roughness, material grain sizes, and thin-film coatings. The nanometer is ubiquitous across modern science because it describes both biological and technological structures at the frontier of research.
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.