Jets form one of the most important quantities to reconstruct at a hadron collider and many searches and measurements are dominated by the uncertainties on the jet energy scale. The procedure of calibrating ATLAS Anti-kt R=0.4 jets using in situ techniques and extrapolation to other radii is presented. Missing transverse momentum (MET) is used to infer the presence of high transverse momentum neutrinos or other weakly interacting neutral particles. The reconstruction and performance in data and simulation of the MET obtained with different class of jets including Particle Flow jets and different pile-up suppression schemes are presented. The performance of a new definition of the MET based on the resolutions of the individual objects to form an estimator for the MET resolution is also shown.