© 2021Turkey, which has immense solar potential, has recently shifted towards solar energy and new renewable energy deployment regulations, including implementation and commercializing rooftop PV technologies. Thus, these require a detailed assessment to determine the power source's capability and convince the policymakers. To the authors' best knowledge, there is no available data or a city-based study for the rooftop PV potential in Turkey. Here, we present the first city-based rooftop PV potential study in Ankara. The technical PV potential calculations are sensitive to the suitable area ratio, module efficiency, and module area assumptions. This study proposes a new, free, reliable, and open-source model for estimating the rooftop PV potential, and it is adaptable to every roof type. The suitable roof area for PV panels is calculated using Helioscope software. Five different modules with different efficiencies and module sizes are modelled in Helioscope. The results showed that Ankara's total technical PV potentials for residential, public, and commercial buildings are 1.15 TWh/year, 55 GWh/year, and 26.8 GWh/year, respectively. Best results are obtained by Mono-Si Halfcut (M2) and Thin Film (M5) modules in residentials, M2 and Mono-Si Bifacial Modules (M3) in Public and Commercial Buildings.