The interaction of point-defects with an external stress eld or with other structural defects is usually well described within continuum elasticity by the elastic dipole approximation. Extraction of the elastic dipoles from atomistic simulations is therefore a fundamental step to connect an atomistic description of the defect with continuum models. This can be done either by a tting of the point-defect displacement eld, by a summation of the Kanzaki's forces or by a linking equation to the residual stress. We perform here a detailed comparison of these dierent available methods to extract elastic dipoles, and show that they all lead to the same values when the supercell of the atomistic simulations is large enough and when the anharmonic region around the point-defect is correctly handled. But for small simulation cells compatible with ab initio calculations, only the denition through the residual stress appears tractable. The approach is illustrated by considering various point-defects (vacancy, self-interstitial and hydrogen solute atom) in zirconium, using both empirical potentials and ab initio calculations.