A calibration method for calibrating an optimum take over height of a substrate in a lithographic apparatus between a substrate table and an ejector element moveable to load and unload the substrate from the substrate table, the method including clamping the substrate on one of the substrate table and ejector element; moving the ejector element between an unloaded state wherein the substrate is supported by the substrate table and a loaded state wherein the substrate is at least partly supported by the ejector element; determining a reference height of the ejector element at the moment that the weight of the substrate is at least partly taken over between the substrate table and the ejector element; and determining the optimum take over height for the ejector element from the determined reference height.