A computational and experimental study of the heat and fluid flow occurring in weld pools during gas tungsten arc welding of Type 304 stainless steel is carried out. A two-dimensional, time-dependent, axisymmetric, numerical model, based on a finite element approach, was developed. Great emphasis was put on the capability of the model to deal with simulations using highly resolved grids. The rather complete model considers buoyancy, electromagnetic and surface tension forces and additionally weld metal vaporisation and the temperature dependence of the coefficient of surface tension. To confirm the predicted characteristic weld pool shapes a comparison with experiments on GTA-welded Type 304 stainless steel plates is presented. Welds on steel containing extra low sulphur and high sulphur were carried out for different times and for varying heat input conditions. The electrode was held stationary and the work-piece was cooled by a copper plate. The experimentally obtained weld pool shapes coincide with the ones predicted in the computations. For welds on steels with low sulphur content it is found that the weld pool shape is deeper at the periphery than at the center at early times, while the depth at the center increases as times proceeds. Increasing the heat input the weld pool shape can be mainly characterised by the formation of two grooves: one at the periphery and one at the weld pool center which is deeper than the one at the periphery. A higher sulphur content in the base material deepens, as expected, the weld pool, while the width of the weld pool is decreased. Based on this comparison the mechanisms behind the development of the different weld pool shapes are explained.