The SOL power decay length (lq) deduced from analysis of fully attached divertor heat load profiles from two tokamaks, JET and ASDEX Upgrade with carbon plasma facing components, are presented. Interpretation of the target heat load profiles is done using a 1D-fit function which disentangles the upstream lq and an effective diffusion in the divertor (S), the latter essentially acting as a power spreading parameter in the divertor volume. It is shown that the so called integral decay length lint is approximatively given by lint lq + 1.64 ¥ S. An empiric scaling reveals parametric dependency lq/mm ~ 0.9 . B­0.7 qcyl PSOL Rgeo for type-IELMy H-modes. Extrapolation to ITER gives lq ~ 1mm. Recent measurements in JET-ILW and from ASDEX Upgrade full-W confirm the results. A regression for the divertor diffusion S is not yet achieved due to the large effect of different divertor geometries of JET and ASDEX Upgrade.