PURPOSES : In this study, the wetting band depths of road slopes estimated using numerical analyses and one-dimensional empirical equations were evaluated. METHODS : The one-dimensional empirical equations used in this study to estimate the wetting band depth were the Pradel and Raad equation, based on modifying the Green and Ampt equation, Lumb's equation, and Sun equation. The numerical analysis of a finite load slope model was carried out using the Seep/w program (2D). In particular, the effect of the initial suction, which indicated the effect of the antecedent rainfall based on the soil–water characteristic curve, was examined as one condition. The results of the wetting band depths obtained using the empirical equations were evaluated and compared with those of the numerical analysis. RESULTS : The wetting band depths obtained using one-dimensional empirical equations were greater than those from the analytical results. In the case of empirical equations, the estimated results obtained for the wetting band depth might be misleading because it has the limitation of being expressed using a one-dimensional equation with an error, owing to several assumptions for the water infiltration phenomenon. It was also found that the accuracy of the wetting band depth was closely related to the results of the soil–water characteristic curve. CONCLUSIONS : Because the wetting band depths obtained using the empirical equation may lead to overestimation, the slope stability could be evaluated as low; however, there was an advantage in terms of inducing conservative design of the road slope. In addition, it was confirmed that the estimated value of the wetting band depth obtained using the Pradel and Raad equation varied with the suction and volumetric function ratios, and further attention should be paid to these two variables.