Computational fluid dynamics (CFD) modelling may help patients with heart defects by predicting blood flow after interventions thus aiding surgical planning. Current CFD-techniques are not clinically feasible due to long computational times. We compared a simplified CFD technique to the state-of-the-art advanced CFD and validated the results with Magnetic Resonance Imaging. We could show that the simplified CFD method on a conventional laptop saved between 75%-99% computing time compared with advanced CFD on a dedicated computation server with comparable accuracy in results of flow distributions. This simplified CFD method may facilitate the implementation of CFD predictions in a clinical setting.