Can I Add a VR Flow? On the Maximum Capacity of 5G to Support 360° Video

360° Video is gaining popularity thanks to the increasing prevalence of Virtual Reality (VR) devices. This has motivated novel approaches to improve the efficiency of 360° Video transmission, with techniques that range from content distribution techniques (using edge servers) to the so-called viewport or tile prediction. In this paper, we take a different approach and study the maximum capacity of a 5G cell to support 360° Video flows. Specifically, we provide a methodology to estimate the upper bound on the number of simultaneous 360° Video flows that can fit the cell. To this aim, we first define different quality profiles for video transmission, which are based on subjective video quality metrics. This upper bound is calculated as a function of the quality profile of the video transmission. We also analyze the impact of different parameters on the results, including scenarios with interfering cells. Our results quantify the ability of 5G cells to support VR traffic and the impact of the type of video or the quality of experience on performance.