We report a universal power law between bulk modulus and molar volume that holds for metallic glasses (MGs) and most polycrystalline metals, which demonstrates that the volumetric derivative of energy minima can be determined by the average atomic volume. Our findings reveal a characteristic size rang of the short-range order of 0.23-0.32 nm in MGs that is closest to that in face-centered cubic metals. More interestingly, the short-range order in noncrystalline and crystalline metals seem to be self-similar from a viewpoint of the compressibility. [http://dx.doi.org/10.1016/j.scriptamat.2013.08.022] The article was published as: Jiang MQ,Wilde G,Gao JB,Dai LH. A universal power law for metallic glasses. SCRIPTA MATERIALIA, 2013, 69(10):760-763, doi: 10.1016/j.scriptamat.2013.08.022