Precision electroweak measurements with ATLAS

The electroweak sector of the Standard Model can be tested via precision measurements of fundamental observables: the effective leptonic weak mixing angle and the W-boson mass. The ATLAS collaboration has recently measured the W-boson mass using data collected during Run 1 at a centre-of-mass energy of 7 TeV: mW= 80370+/-19 MeV and the effective leptonic weak mixing angle using data collected at 8 TeV: sin2theta_eff^l = 0.23140 +- 0.00036. These results have a precision similar to those of the published Tevatron results and to the most precise individual observable measurements from lepton colliders.