A laser beam profiler (LBP) is essential for characterizing laser beams by providing detailed intensity distribution measurements using internationally standardized algorithms. Typically expensive, LBPs are often inaccessible to low-budget research labs. To solve this, "Beamdiameter", an open-source software, converts affordable CMOS or CCD image sensors into effective profiling devices adhering to ISO-11146 standards. Developed in Python with a PySide6 interface, Beamdiameter captures precise laser beam profiles, determining parameters like eccentricity and beam width. Its real-time operation is valuable for immediate feedback in microfabrication and scientific experiments. Beamdiameter's open-source nature fosters collaboration, transparency, and customization in the scientific community.