The coin grading scale is very important to finding the value of a coin. The Sheldon coin grading scale, which is the most common grading scale and is used by the grading services, contains grades from 0 to 70, with 70 being the best and 0 being the worst. One or two letters are in front of the number to include the more overall grade.
The grading scale is especially helpful if you're new to coin collecting and is unaware of coin grades and would like to learn or is just curious what those numbers on the coin slabs by PCGS, NGC, ANACS, and IGC mean.
P-00 (No Grade): This "grade" is used for coins in which the coin, date, and/or mintmark cannot be identified. This grade is used only for coins in very bad condition. This grade is not used by the popular grading services, like PCGS and NGC.
P-01: This is used when the date, type, and mintmark can be identified, but the other details cannot. The rims are worn, the high details are gone, and the coin is in poor condition.
FR-02: The coin is in poor condition, the rims are barely visible, and few details are visible.
AG-03: Most letters and details on the the coin are visible and/or readable.
G-04: Letters are mostly full, but rims are worn.
G-06: Letters and many details are full and the rim is less worn.
VG-08: The entire coin is worn and letters, while full, are soft.
VG-10: The entire coin is worn and the letters, while full, are soft, but sharper than VG-08.
F-12: Letters are sharp, but parts of the coin are still worn.
F-15: Letters are sharp, but parts of the coin are slightly worn.
VF-20: Details are not sharp, but all shown to some extent.
VF-25: Almost complete details, but many design areas are soft.
VF-30: Almost complete details, and the design areas are sharper than VF-25.
VF-35: While wear is clear, all details are shown clearly.
EF-40: Also known as XF-40, minor wear is on the high details.
EF-45: Also known as XF-45, minor wear is on some of the high details.
AU-50: Slight wear is obvious, especially on the high points.
AU-53: Slight wear can be seen, but mostly on the high points.
AU-55: Slight wear can be seen, but only on the high points.
AU-58: Slight wear can be seen only on the highest points of the coin.
60-70 is reserved for uncirculated and proof coinage that is uncirculated. Uncirculated coins that were meant for circulated or had a circulating finish will get an MS, or mint state grade, while proof coins that were meant for collectors with a special proof finish and careful handling will get a PR, or proof grade. PR can also be stated as PF. The lower grades in these categories are reserved for coins with several marks and imperfections, while the higher grades are reserved for coins with no marks or incredibly minimal marks and exceptional eye appeal.
One can use this scale to grade your coins yourself* or to provide an approximate estimation of the grade of a coin you're about to send off to be graded.
*If you grade a coin yourself, it will most likely not be the exact correct grade that a company like PCGS would give it. Please be aware that any grade you put on a coin is mostly for your own use and should not be used to sell a coin.