The characterisation of the Higgs boson relies on the determination of its properties, including its mass, which is a free parameter in the SM, and its width. Here we review the latest measurements of the Higgs boson mass and width in the four-lepton final state at a center-of-mass-energy of 13 TeV with the CMS detector. The most precise measurement of the Higgs boson mass in a single channel $m_{H} = 125.04 \pm 0.12$ GeV is derived using the full CMS Run 2 data set corresponding to a total luminosity of 138 fb$^{-1}$. The resulting on-shell mass measurement leads to an upper limit on the Higgs boson width of $\Gamma_H < 60$ MeV at 68 \% confidence level. By combining the on-shell and the off-shell measurements in the four-lepton final state, the value of the Higgs boson width of $\Gamma_H = 2.9^{+2.3}_{-1.7}$ MeV is obtained.