Hybrid metal‐halide perovskite‐based thin‐film photovoltaics (PVs) have the potential to become the next generation of commercialized PV technology with certified power conversion efficiencies reaching 24% on devices having 0.1 cm2 area. Recent efforts in upscaling this technology result in an efficiency of 12.6% for 354 cm2 modules. However, upscaling loss for perovskite‐based PVs is higher than for any other PV technology. In this study, upscaling losses of devices with aperture area 0.1, 4, and 100 cm2 are investigated, with a focus on layer inhomogeneities. Electroluminescence, dark lock‐in thermography, microphotoluminescence spectroscopy, and electron spectroscopy are used to analyze and group layer inhomogeneities with a minimal size of 10 μm and to compare loss mechanisms for radial and linear deposition techniques. Analysis results help to identify current processing pitfalls, where understanding and control of perovskite crystal formation plays the crucial role.