Titanium diboride is widely known as a superhard material achieving an indentation hardness of 40 GPa and beyond. Coatings of TiB₂ produced by DC magnetron sputtering are typically in the superstoichiometric regime regarding the B/Ti-ratio in a range of TiB₂.₄ to TiB₃.₅. This surplus in Boron is attributed to a different radial distribution of Boron and Titanium during the deposition process and forms a tissue phase which is highly relevant for the material’s mechanical properties. A reduction of Boron content in the coating would thus mean a reduction of B-rich tissue phase formed and consequently a clear change in e.g., hardness or fracture toughness. Earlier works have already shown an increase in fracture toughness (measured by microcantilever bending) of DC-sputtered TiB₂ when reducing the B/Ti-ratio from 4.4 to 2.1. There have also been reports of even higher fracture toughness in understoichiometric TiB1.43 produced through HiPIMS and measured by cube corner indentation, although films grown by DC showed a decrease in KC with decreasing B-content. In the current work, we aim to show how the mechanical properties of TiB₂ change when crossing the stoichiometric point by DC and HiPIMS sputter deposition. The stoichiometry of DC-grown films is controlled by placing pieces of pure Ti along the race track of the target, while in HiPIMS mode it is controlled by varying the pulse on-time as well as adding pieces of Ti. The films are analysed through XRD and SAED for structural information, ICP-OES to determine the B/Ti-ratio as well as SEM and TEM for microstructure. Hardness and Young’s Modulus are measured by nanoindentation while KIC values are determined by cube corner indentation and microcantilever bending to investigate the influence of stresses.