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The effective number of relativistic neutrino species is a fundamental probeof the early Universe and its measurement represents a key constraint on manyscenarios beyond the Standard Model of Particle Physics. In light of this, anaccurate prediction of $N_{\rm eff}$ in the Standard Model is of pivotalimportance. In this work, we consider the last ingredient needed to accuratelycalculate $N_{\rm eff}^{\rm SM}$: standard zero and finite temperature QEDcorrections to $e^+e^- \leftrightarrow \nu\bar{\nu}$ interaction rates duringneutrino decoupling at temperatures around $T\sim {\rm MeV}$. We find that thiseffect leads to a reduction of $-0.0007$ in $N_{\rm eff}^{\rm SM}$. This NLOQED correction to the interaction rates, together with finite temperature QEDcorrections to the electromagnetic density of the plasma, and the effect ofneutrino oscillations, implies that $N_{\rm eff}^{\rm SM} = 3.043$ with atheoretical uncertainty that is much smaller than any projected observationalsensitivity.

Neff in the Standard Model at NLO is 3.043