Traditionally, the bearing capacity and the settlement of footings on clay are determined independently by theoretical analyses: the bearing capacity for short-term conditions and the settlement for long-term conditions. Bearing capacity methods usually assume that the clay has a rigid-plastic behaviour and they neglect prefailure deformations. Conventional settlement methods ignore failure conditions. However, field load tests give load–settlement curves in which it is impossible to dissociate settlement and bearing capacity.This paper examines whether the calculated theoreticalqultis realistic. A long-term load–settlement curve can be easily calculated using an oedometric equation. The curve ofsoed/Bversus load is a good approximation of the true long-term settlement curve and can be used to determine whether the (short-term) bearing capacityquis realistic: ifsoed/Bhas a high value for a load smaller than the computedqu, it means that thisquis not a valid evaluation of the bearing capacity, the true value of which remains unknown. To establish when conventional analyses give erroneous bearing capacities four cases are analyzed, encompassing the influence of the compressibility of the clay material and the influence of downward groundwater gradients on the compressibility. The results show that groundwater conditions have a major influence upon the bearing capacity of highly compressible, slightly overconsolidated clays but practically no influence upon the bearing capacity of clays of low compressibility.Key words: shallow foundations, clay, deformability, bearing capacity, settlement.