United States coins are most often graded with the American Numismatic Association (ANA) grading scale. The ANA is a non-profit group created in 1891 and chartered by Congress since 1912.
ANA Grading Scale Summary
Perfect Uncirculated (MS-70) is in perfect new condition, showing no trace of wear. The finest quality possible, the coin has no evidence of scratches, handling or contact with other coins. Very few regular issue coins are ever found in this condition.
Choice Uncirculated (MS-65) is above average, may be brilliant or lightly toned, with very few contact marks on the surface or rim. MS-67 through MS-62 indicates slightly higher or lower grades of preservation.
Uncirculated (MS-60) has no trace of wear but may show a number of contact marks and surface may be spotted or lack some luster.
Choice About Uncirculated (AU-55) shows the barest evidence of light wear on only the highest points of the design. Most of the mint luster remains.
About Uncirculated (AU-50) has traces of light wear on many of the high points. At least half of the mint luster is still present.
Choice Extremely Fine (EF-45) shows light overall wear on highest points. All design details are very sharp. Some of the mint luster is evident.
Extremely Fine (EF-40) is lightly worn throughout the design, but all features are sharp and well defined. Traces of luster may show.
Choice Very Fine (VF-30) has light even wear on the surface and highest parts of the design. All lettering and major features are sharp.
Very Fine (VF-20) shows a moderate amount of wear on the high points of the coin’s design. All major details are clear.
Fine (F-12) shows moderate to considerable even wear throughout. Entire design is bold with an overall pleasing appearance.
Very Good (VG-8) is well-worn with main features clear and bold although rather flat.
Good (G-4) is heavily worn with the design visible but faint in areas. Many details are flat. Common coins in “Good” condition are not particularly desirable pieces for collectors. Rare or valuable coins in this condition, however, are often saved when no others are available.
About Good (AG-3) is very heavily worn with portions of lettering date and legends worn smooth. The date may be barely readable.
For more details and illustrations, the Official ANA Grading Standards for United States Coins is available through book sellers.