The rates of loss of calcium in eight Scottish catchments on four rock types have been calculated by three methods: (1) long-term rates from elemental depletion in soil profiles; (2) using the PROFILE model; (3) current rates from input-output budgets. The first two methods are soils based and yield rates which, with one exception, are lower than the current rates. Although comparisons of the values obtained by the three methods are complicated by the different assumptions inherent in the methods, the current rates are often an order of magnitude higher and presumably indicate sources of weatherable calcium-bearing minerals in the catchment outwith the soils.