Abstract Digital holography is a technology with a potential to provide realistic 3D images. However, generation of digital holograms is a computationally demanding task. Thus, the performance is a major concern. We propose a new method that reduces spatial resolution in order to accelerate hologram generation. It employs the propagation between parallel planes for efficient optical field values evaluation and a computer graphics approach for approximating visibility. Our results show that the proposed reduction has only a minimal impact on the visual quality, while the formal computational complexity confirms performance improvement. Keywords Digital holography · Hologram generation