There is provided a quantitative method for determining a level of a sanding surface preparation of a carbon fiber composite surface, prior to the carbon fiber composite surface undergoing a post-processing operation. The quantitative method includes fabricating a ladder panel of levels of sanding correlating to an amount of sanding of sanding surface preparation standards for a reference carbon fiber composite surface of reference carbon fiber composite structure(s); using surface analysis tools to create target values for quantifying the levels of sanding; measuring, with the surface analysis tools, sanding surface preparation location(s) on the carbon fiber composite surface of a test carbon fiber composite structure, to obtain test result measurement(s); comparing the test result measurement(s) to the levels, to obtain test result level(s); determining if the test result level(s) meet the target values; and determining whether the carbon fiber composite surface is acceptable to proceed with the post-processing operation.