Wall shear stress (WSS) is an increasingly used vessel wall parameter derived from 4D Flow-MRI data. There is no reference standard for evaluating WSS and different software approaches are available. However, their comparability is not known. Hence, it was the aim of this study to compare two available software tools (GTFlow and FlowTool). To achieve this goal, data from 21 healthy volunteers scanned on MRI scanners of different vendors were analyzed with respect to average and segmental WSS. Results showed good agreement between tools.