In this talk, we present the latest study of e + e − → t ̄ t , based on a detailed simulation of the ILD detector concept, which assumes a centre-of-mass energy of √ s = 500 GeV and a luminosity of L =500fb − 1 , equality shared between the incoming beam polarisations of P e − ,e + =( ± 0 . 8 , ∓ 0 . 3). The study comprises the cross sections, the forward-backward asymmetry and the slope of the helicity angle asymmetry. The vector and axial vector couplings are separately determined for the photon and the Z component. The tensorial CP -conserving coupling can be also extracted by assuming the other couplings to be the SM values. We show that the sensitivity to new physics would be dramatically improved with respect to what is expected from LHC for electroweak couplings