PCGS Specials

HomeCoinWeek PodcastRon Guth Proposes 100-Point Coin Grading Scale

Ron Guth Proposes 100-Point Coin Grading Scale

We discuss the Guth 100-Point Coin Grading Scale in this week’s CoinWeek Podcast. Click to listen.

On Monday, Ron Guth, the 2014 American Numismatic Association’s (ANA) Numismatist of the Year and former president of PCGS, released a statement advocating for the adoption of a new 100-point coin grading scale.

According to Guth, the Guth 100 Point Coin Grading Scale would benefit collectors who are confused as to why the industry-accepted grading system, adapted from a pricing scale for 1794 cents published in William Sheldon’s 1958 numismatic book Penny Whimsy, uses the number “70” to denote perfection. Sheldon based this number on what was then the market price for the finest 1794 cents in existence.

The current system, more an homage to Sheldon and not a direct recreation of his system, grades coins on a scale from 0 to 70, zero being almost unrecognizable and 70 being theoretically perfect. Professional grading services, such as PCGS and NGC, have adopted this system and evolved it over the years. Currently, both services assign Mint State coins and some About Uncirculated coins a plus grade if they are at the top end of the grade. NGC also assigns a Star Designation for coins with superior eye appeal.

Guth sees moving to a 100-point system as a way to stop having to answer the question, often posed by novices, “why is 70 the perfect score”. Guth feels that, psychologically, 100 is a number more in line with what people assign to perfection.

Guth’s system more or less leaves the current system in place for grades up to AU-58. As is the case with the current system, not every number from 0-58 is utilized. In the place of plus grades, Guth advocates the use of the next integer up. An MS-65+ in the Guth system would be described as an MS91.

To eliminate confusion between the old and the new coin grading system, Guth’s 100-point system does not use grades 60-70 and instead uses the grades 80-100 to denote Mint State and Proof grades.

In a press release issued to the media, Guth explains the reason why 20 grades are needed for top-end coins.

“Currently, the coin market squeezes plus or half grades, known as split grades, into the 60 to 70 range. The Guth 100 Point Coin Grading Scale℠ assigns whole numbers to split grades and eliminates decimals, rounding, and pluses.” 

The following chart shows the conversion between the current system and Guth’s 100 point system:

More information about Guth’s 100 Point Grading Scale can be found at his website, www.ExpertNumismatics.com.

Coinweek is the top independent online media source for rare coin and currency news, with analysis and information contributed by leading experts across the numismatic spectrum.

Related Articles


  1. Guth must have visited ANA HQ and gotten high from second-hand weed smoke. We can’t get 70 points right. How does having 30 more help anything? Rick Snow’s System from Anaheim ANA had more merit than this, and has gone nowhere. We have ZERO need to reinvent the wheel. We just need better wheel makers.


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Stacks Bowers Auction

L and C COIN Specials

Doug Winter Numismatics Branch Mint Gold