Embankment widening alongside an existing embankment causes additional stress and differential settlement on the foundation beneath the embankment, which may have adverse effects on pavements. The settlement profiles of the existing and widened foundations beneath an embankment are governed by several geometric and physical parameters related to embankment widening. An accurate settlement evaluation method is essential for the determination of an appropriate ground improvement technique. In this paper, a simplified method for predicting the settlement of the soft foundation induced by embankment widening is proposed. A validated finite element method model was first employed to quantify the effect of geometric parameters and soil properties on the settlement characteristics. Furthermore, a simplified model based on the bi-Gaussian function was developed to illustrate the settlement profiles. The results obtained by the proposed model are in good agreement with previously reported centrifuge test results and a generated numerical database, demonstrating that the proposed model has satisfactory accuracy. The developed prediction model offers an alternative approach for the preliminary design of embankment widening.