In recent decades, numerous excavations have been conducted at prehistoric sites in northwestern Iran, and the results of these studies have contributed to the development of a chronological framework for the region. The early Chalcolithic period in this area is referred to as the Dalma or Hasanlu X period. Various theories have been proposed regarding the chronological span of this culture, yet challenges and debates about its dating remain. The Belachak 3 site is one of the settlements attributed to this period, excavated by the first author of this article. The excavation results indicate that the site was temporarily occupied. The pottery recovered from this site closely resembles the ceramics found at well-known Dalma sites such as Dalma Tepe and Nad Ali Beig. This article aims first to explore the relative and absolute chronology of the Belachak 3 site. Subsequently, it evaluates the dating of this culture based on the absolute chronology of this and other Chalcolithic sites in western and northwestern Iran. For dating Belachak 3, five animal bones were sent to the Poznań Radiocarbon Laboratory. The results indicate that the site was occupied around 5000–4700 BCE. Additionally, based on the pottery findings and absolute dating, it can be suggested that the Dalma culture likely emerged in the late 6th millennium BCE and became widespread across large areas of western and northwestern Iran from around 5000 BCE onward.