Convert Atomic Mass Unit (u) to Carat (car, ct) instantly.
About these units
Atomic Mass Unit (u)
The atomic mass unit (u) is defined as exactly 1/12 the mass of a neutral carbon-12 atom, which makes it approximately 1.66053906660 × 10⁻²⁷ kilograms. This definition allows scientists to express atomic and molecular masses in a convenient, intuitive scale that aligns with the structure of the periodic table. By anchoring the unit to carbon-12, chemists and physicists gained a universal reference point that harmonizes molecular weight, relative isotopic abundance, and mass spectroscopy results. The atomic mass unit effectively normalizes the complexity of atomic masses into whole-number or near-whole-number values for most nuclei. In chemistry, u is indispensable for calculating molar masses, reaction stoichiometry, and isotopic compositions. It is also used across nuclear physics, astrophysics, and biophysics, demonstrating the universality of atomic-scale measurement.
Carat (car, ct)
The carat, equal to 200 milligrams, is the standard unit for measuring gemstones and pearls. Its origins trace to the seeds of the carob tree, which were historically thought to have remarkably uniform mass, making them convenient reference weights for early traders. In the modern gem trade, carats measure both weight and (informally) influence perceived value—though size and quality factors such as clarity and color also play major roles. High-precision digital scales capable of reading to 0.001 carat are common in gemology. The carat's persistence shows how specialized units evolve to meet the needs of niche industries. Though small, its economic impact is enormous due to the value of gemstones.