The current LHC experimental program is scheduled to last until the end of 2023 and to result in a total data sample of about 300~fb$^{-1}$ at a $pp$ centre-of-mass energy close to the design value of 14~TeV. This will be followed by a high-luminosity phase in which the LHC instantaneous luminosity will be increased by a factor of up to 7.5 times the design value of $1\times 10^{34}\,{\rm cm}^{-2}{\rm s}^{-1}$, with the goal of accumulating a total dataset of about 3000~fb$^{-1}$ over about a ten-year run period. This will require significant upgrades to both the accelerator infrastructure, and the detectors, which were not designed to operate under these conditions. The large anticipated data sample will allow for more precise investigations of topics already studied with the 300~fb$^{-1}$ data sample, as well as for studies of processes that are accessible only with the much larger statistics. There will be a particular focus on investigations of the properties of the Higgs boson, which was discovered in 2012. Rates and signal strengths will be measured for a variety of production and decay modes, allowing extraction of the Higgs boson couplings. Particular final states will allow differential cross-sections to be measured for all production modes, and for studies of the Higgs width and CP properties, as well as the tensor structure of its coupling to bosons. An important part of the HL-LHC experimental program will be investigations of the Higgs self-coupling, which is accessible via studies of di-Higgs production. The program of other Standard Model measurements will also continue at the HL-LHC. Topics that have been investigated so far, for the HL-LHC, include Vector Boson Scattering as well as topics in $b$- and top-quark physics. Here, projections for performance at the HL-LHC will be discussed for both ATLAS and CMS.