Convert Atomic Mass Unit (u) to Femtogram (fg) 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.
Femtogram (fg)
A femtogram is 10⁻¹⁵ grams, an extraordinarily small unit used primarily in molecular biology, analytical chemistry, and particle science. At this scale, masses correspond to small clusters of molecules, fragments of genetic material, or trace contaminants in environmental samples. In genomics, for example, the femtogram level may represent the mass of DNA extracted from just a few cells, pushing the limits of current sequencing technologies. Advanced mass spectrometers and nanoscale resonators can detect femtogram-level differences, revealing chemical changes invisible at larger scales. The femtogram symbolizes the reach of modern science into realms once thought beyond measurement. As techniques continue to improve, femtogram-level precision will become increasingly common in nanotechnology and biophysics.