Probabilistic analyses were performed to estimate consolidation settlements using an extensive field and laboratory data set from the Namak New City site in Korea. The results from 70 borings, 106 Dutch-cones and 103 oedometer tests were statistically analyzed. An analytical approximation method was developed and compared to Monte Carlo simulation techniques to estimate distributions of settlement ratios. Among the parameters of interest, the most dominant factor that controlled the magnitude of settlement was the soft clay thickness. For fill heights of 3 to 9 m, average settlement ratios of 11.1 to 21.0 % were estimated from the probabilistic approach. The settlement distributions from the analytical approximation were comparable to that from the Monte Carlo simulation.