Scientists are developing a new measurement standard that redefines the kilogram using a fixed value of the Planck constant, a fundamental number in quantum physics. Led by NIST alongside international oversight bodies like CIPM and CGPM, plus national metrology institutes across Canada, Switzerland, Korea, France, New Zealand, and the International Bureau of Weights and Measures, this protocol aims to replace the last physical artifact-based unit with a universal constant. The proposal is currently under review, with standards organizations waiting for independent laboratories to meet strict agreement criteria before granting final approval.
The standard relies on advanced measurement protocols called watt balances, which determine mass by comparing it to electromagnetic forces, alongside an alternative method that counts atoms in an ultra-pure silicon sphere. In simple terms, multiple labs must independently arrive at the same constant value within very tight error margins, ensuring global consistency and reliability. Once adopted, this approach will enable highly precise “electronic kilograms” that improve measurement accuracy across scientific research, advanced manufacturing, and emerging quantum technologies that require exact fundamental constants for calibration, control, and system stability.
Officials aim to begin trial implementations as early as 2015, with full international rollout expected shortly after all participating labs satisfy the required precision thresholds. Upgraded measurement devices will replace older, complex equipment, streamlining operations and ensuring that future mass measurements remain consistent worldwide. This transition marks a major step toward standards grounded in unchanging laws of nature rather than physical objects, supporting both classical industry and next-generation quantum systems.
Keywords: Planck constant, watt balance, SI base units
