Si02 and Ti02 sol-gel thin films were prepared from solutions of different concentration. To fit the experimental coating thickness values, the modification of two theoretical equations, available from the literature, was used. The best-fit results were given by the approach which relates the thickness to the square root of the velocity. It was shown that, provided the same heat treatment is used for the films, the thickness of coatings obtained from solutions of different concentration and at anywithdrawal speed may be predicted from just one thickness value obtained at one withdrawal speed. if the solutions' viscosity and density, are known.