  The current status of electroweak precision tests after the discovery of the
Higgs boson is reviewed, both from a phenomenological and from a theoretical
point of view. Predictions for all Z-pole quantities are now available at the
complete fermionic two-loop order within the Standard Model. The calculation of
these corrections is described based on the example of the total Z-boson width.
Finally, an outlook on the experimental improvements and theoretical challenges
for a future high-luminosity e+e- collider is given.
