Here, we present an analytical procedure to extract the anisotropy constants of antiferroelectric (AFE) materials from a few key features of the experimental polarization versus field curves. Our approach is validated for two experimental datasets of ZrO 2 capacitors, and the extracted parameters are consistent with the microscopically nonpolar nature of the zero-field state of the AFE ZrO 2 . The methodology has applications in AFE nonvolatile memories and memristors, as well as in electron devices exploiting the negative capacitance (NC) operation of ZrO 2 .