S (Superb) Exceptionally large margins with mathematically perfect centering. Often noted as being: "a Gem", "Finest copy extant", "perfection", "finest possible for the issue", etc. Items in superb condition command high premiums, usually at a multiple of catalog value.
EF (Extremely Fine) Exceptionally large margins with near perfect centering. Items in extremely fine condition command premiums, usually at a multiple of catalog value.
VF (Very Fine) Normal size margins for the issue and well-centered, with the stamp design just slightly closer to one or more sides.
F (Fine) Smaller margins than usual, and visibly off-center. In the case of many pre-1890 issues, the stamp design may be touched in places.
VG (Very Good) The margins or perforations touch the stamp design in one or more places. In many cases for 19th Century perforated issues, the VG designation should not be used because perforations touching the design are the norm, with well­centered copies demanding high premiums
G (Good) The margins or perforations are well into the design, and the stamp usually is accompanied by other faults.