On the 16th of November 2018, at the general conference on weights and measures in Versailles, representatives from 57 nations voted to change how the standard one kilogram measurement is derived.

The kilogram was currently the only metric unit still based on a physical artefact - a platinum-iridium cylinder stored under three sealed bell jars at the international bureau of weights and measures (BIPM) in Sèvres.

Going forward, the kilogram will be derived from a fundamental constant of nature, the Planck constant, which links the amount of energy a photon carries with the frequency of its electromagnetic wave. This offers more stability as fundamental constants don’t change over time.