Abstract An ensemble of mass tables is generated by extrapolating with the transverse Garvey-Kelson equation from different subsets of experimentally known masses. Predictions of unknown masses are obtained by averaging over the ensemble. The averaging procedure also yields the uncertainties accompanying these predictions. No parameters are used. Results for some 4400 masses in the range 12 ≤ A ≤ 254, 5 ≤ Z ≤ 100, Z < N ≤ 155, and Z = N for even- Z are presented in the main table in this issue. The average absolute deviation between experimentally known masses and their predictions is 102 keV.