Embodiments generally describe systems, devices, and methods for focusing and calibrating beam profilers. A test object is provided that may include an internal housing rotatable within an external housing. The internal housing may house a light source, a collimator, a filter, and/or a diffuser. A plate may be mounted to the internal housing and may include a plurality of markings. In some embodiments, to focus a beam profiler, the test object may be positioned adjacent the converter plate of a beam profiler. Marker images may be captured and a focus quality may be assessed therefrom. A position of the converter, objective, and/or camera of the beam profiler may be adjusted based on the focus quality. To calibrate, images of the markings in several rotational positions may be captured and used for calibration. The markings may be rotated to several positions by rotating the internal housing relative to the external housing.