physics-units-si

SI units, CODATA constants, dimensional analysis, and rigorous unit conversion. Use when extracting, normalizing, or computing physical quantities (energy, frequency, length, mass, time, temperature). Handles eV/keV/MeV/GeV/TeV, Hz/kHz/MHz/GHz/THz, meter/cm/Å/fm, kg/g/u, second/ms/μs/ns/fs, Kelvin/eV-temperature equivalents.