Inverse the mouse position value


I have a GUI button that pops up on the mouse position, only problem is, is that the Y axis is the wrong way round.

If I move my mouse left or right, the button follows the mouse fine, but if I move it up or down, the button moves in the opposite direction. Is there a way to reverse the value?

if(toggleClick == true){
        if(GUI.Button(Rect(Input.mousePosition.x, Input.mousePosition.y, 100, 50),"Pick Up")){ //+50
            toggleClick = false;


You could subtract mousePosition.y from the current Screen.height.