CMS Electron and Photon Performance at 13 TeV

The Compact Muon Solenoid (CMS) detector is one of the two multi-purpose experiments at the Large Hadron Collider (LHC) and has a broad physics program. Many aspects of this program depend on our ability to trigger, reconstruct and identify events with final state electrons, positrons, and photons with the CMS detector with excellent efficiency and high resolution. We present the full process of electron and photon reconstruction in CMS, starting from tracker hits and energy deposits in the electromagnetic calorimeter, the methods to achieve the ultimate precision in Run II energy measurements, the identification strategies (based both on cut-based approach and on multivariate analysis) to discriminate prompt electrons and photons from background, and the methods to estimate the associated systematic uncertainties. Finally the performance on benchmark channels (such as $Z$ → e$^+$ e$^-$) will be shown.