<p>Soil mineral weathering is one of the major sources of base cations (BC), which play a dual role for a forest ecosystem; they function both as plant nutrients, and for buffering against acidification of catchment runoff. On a long-term basis, the soil weathering rates will determine the highest sustainable forest productivity without causing acidification. It is believed that the hydrologic residence time plays a key role in determining weathering rates on a landscape scale. The weathering model PROFILE has been used for almost 30 years to calculate weathering rates in the rooting zone of forest soils. However, the mineral dissolution equations in PROFILE are not adapted for the unsaturated zone, and employing these equations on a catchment scale results in a significant over-prediction of base cation release rates to surface waters. In this study we use a revised set of PROFILE equations which, among other features, include retardation from silica concentrations. Relationships between the water transit time (WTT) and soil water concentrations were derived for each base cation, by simulating the soil water chemistry along a one-dimensional flowpath, using the mineralogy from a glacial till soil. We show how the revised PROFILE equations are able to reproduce patterns in BC- and Si-concentrations, as well as BC-ratios (Ca<sup>2+</sup> / BC, Mg<sup>2+</sup>+ / BC and Na<sup>+</sup> / BC), observed in soil water profiles and catchment runoff. As opposed to the original set of PROFILE equations, the revised set of equations could reproduce how increasing WTT led to decreasing Na<sup>+</sup> / BC, as well as increasing Ca<sup>2+</sup> / BC and Mg<sup>2+</sup> / BC. Furthermore, the total release of base cations from a hillslope was calculated using a mixing model, where water of different WTT was mixed according to an externally modelled WTT-distribution. The revised set of equations gave a 50 % lower base cation release (0.23 eq m<sup>−2</sup> yr<sup>−1</sup>) than the original PROFILE equations, and are in better agreement with mass balance calculations of weathering rates. The results from this study thus demonstrate that the revised mineral dissolution equations for PROFILE are a major step forward in modelling weathering rates on a catchment scale.</p>