Theoretical Coverage. 

This theoretical coverage is based on all of the gold contained in the solution being evenly distributed over the surface being plated. Your results will probably vary from the stated theoretical coverage. This is because brush plating with gold usually results in uneven distribution of the deposited metal and with the brush plating process, varying degrees of the metallic content of the solution is normally wasted by being rinsed off before all of the gold is plated onto the surface.