The kilogram has been officially redefined using a fundamental quantum property known as the Planck constant, replacing the old definition based on a physical metal cylinder. This international standard was developed by the global metrology community and heavily advanced by NIST. It was finalized in late 2018 and fully implemented on May 20, 2019, following several years of research to ensure precision measuring tools could reliably track this quantum reference.
Under the new system, everyday physical weights will still be used for routine calibrations across industries and laboratories, but they now trace back to an unchanging natural constant rather than a manufactured object. This shift establishes a permanently stable measurement foundation that supports ultra-precise scientific work. For emerging technologies like quantum computing, it means calibration standards won’t drift over time, ensuring reliable performance and long-term consistency as advanced hardware continues to scale.
Source: https://www.nist.gov/si-redefinition/kilogram/kilogram-future
Keywords: Planck constant, Kibble balance, SI units
