The transformation to a climate-neutral power grid has created a large demand for inertia, among other things. In the future, the provision of inertia will be supported by generation systems linked to grid-forming (GFM) inverters. Low-voltage consumers can also play a role, as every possible potential should be exploited. In this paper, the calculated and simulated behaviour of a GFM inverter, providing inertia during various frequency faults, is validated in the laboratory. The laboratory setup consists of a GFM test equipment, a grid simulator to recreate different frequency scenarios and a grid replica to test different grid impedances. The resulting power shifts for inertia provision can be successfully validated in the laboratory. The same dependencies can be recognised as in simulative investigations. A higher power shift is necessary with a higher frequency gradient; with a higher start-up time constant T_A, more inertia is provided. The investigated grid impedances do not influence the power shifts. A variation of the active power setpoint value shows that the power shift is added to the investigated active power sequences. After the fault, the inverter returns to its setpoint value. An interaction between an active power setpoint requirement and the GFM inverter is possible.