The authors present a numerical calculation of the edge capacitance corrections for thin unguarded disc electrodes placed on opposite faces of a dielectric sheet or film. As a function of the ratio (a/h) of electrode radius to sample thickness, the correction grows logarithmically for small values of the sample dielectric constant epsilon ₂, but for epsilon ₂>or=20 the correction is almost independent of (a/h). In all cases, the correction decreases in relative importance as (a/h) increases. These calculations yield upper limits for experimental measurements, and provide a theoretical base for modifying the empirical expressions which are currently found in various national and international standards.