What's in a Coin Grade? Why is '70' Perfect?

Grade 70 - What Does it Mean?

A vast majority of coin collectors are quite familiar with the numbers 1-70. These numbers make up the modern coin grading standard known as the Sheldon Scale. In reference to a coin's grade – the appearance or condition of the coin – these numbers represent far more than a random scale. Along with other factors like total number minted, rarity and age of the coin, the grade assigned to a particular coin by a professional coin grader helps the collecting community determine the overall value of the coin.

The need for a standardized scale became more and more apparent as the numismatic hobby grew ever popular over time. The earliest known scale in reference to coins was very minimalistic – a coin was either New or Used. Coin grading evolved from there into a letter system. The most typical grades used in this system became PO for poor (aka basal state), FR (fair), AG (about or almost good), G (good), VG (very good), F (fine), VF (very fine), EF (extremely fine), AU (about or almost uncirculated), UNC (uncirculated), BU (brilliant uncirculated). Some other letter designations have been added more recently, especially for bullion-type coins, including MS (mint state) and PF or PR (proof). Read this article to learn more about all of these letter grades.

The Sheldon Scale is predominately utilized by professional third-party coin grading services. Two of the largest such services in the United States are NGC (Numismatic Guaranty Corporation) and PCGS (Professional Coin Grading Service). Dr. William Herbert Sheldon is credited with coming up with the Sheldon Scale in the 1950s in his book Penny Whimsy. This numerical system made it much easier for a collector to determine what condition a coin was in, without having to stop and think what the letter grade represented. Someone can now simply look at the numerical grade of a coin and have a general idea of the coin's condition – with 70 representing a perfect coin, 69 being near-perfect, and so on down the number scale, with a grade of 1 being assigned to a piece of metal that is barely recognizable as once being a coin.

But why does the scale only go up to the number 70? In terms of Sheldon's book, the scale was initially intended to be a reflection of the relative value of a 1794 Large Cent. A perfect uncirculated version of this coin had a value of $70, while the coin in a basal (or poor) state was worth $1 at the time. Therefore, the theory was that a 70-graded coin would be worth 70 times as much as a 1-graded coin. The 1-70 scale was thus adopted into the community of large copper coin collectors, and eventually garnered more widespread use among the larger numismatic community. For more in depth descriptions of coin grades see this Wikipedia article on the Sheldon coin grading scale.