A method, including performing an initial ablation of a tissue using an electrode in a probe distal end to apply a first power to the tissue, and measuring a change of temperature of the distal end while applying the first power. The method also includes estimating a thickness of the tissue in response to the measured change of temperature, and in response to the estimated thickness, computing at least one of a second power required and a time period for ablation, to complete ablation of the tissue. The method further includes performing a subsequent ablation of the tissue using the computed at least one of the second power and the time period for ablation.
