It is unknown whether the accuracy of DWI-model based estimates of the axonal water fraction could be enhanced by additional calibrations. In this study we compared three DWI-models (WMTI, NODDI, NODDIDTI) using histology data as gold standard in ex vivo mouse models with a broad dynamic range of axonal metrics. We found that all DWI-models improved with additional calibration. Models with fixed diffusivities benefited efficiently from an additional scaling, while the WMTI model was stronger affected by an additional offset. Furthermore, without any additional calibration, the axonal compartment biomarker from NODDIDTI could explain the data better than WMTI or NODDI.