Coin Grading Explained

The Sheldon Scale, From 1 to 70

Every grade you see on a slab or in one of our catalogs comes from the Sheldon scale, a 70-point system Dr. William Sheldon introduced in 1949. His original idea was about price: a coin grading 70 should be worth seventy times a coin grading 1. The pricing math did not survive, but the scale did. PCGS built its grading standards on it in 1986, when it introduced encapsulated third-party grading, and NGC adopted it in 1987 when it began operations. Today both services, and the entire American coin market, speak in the same numbers.

The scale runs from Poor 1, a coin with just enough detail to identify the date and type, up to a perfect 70, which NGC defines as a coin with no post-production imperfections at 5x magnification. Not every number between gets used. Below 60 the services skip around: grades jump from 4 to 6 to 8, from 15 to 20, from 45 to 50. From 60 up, every number counts, because that stretch is where most of the money lives. Sixty is the threshold: a coin at 60 or above is uncirculated, meaning it never passed hand to hand in commerce, and everything below it is a circulated coin graded by how much wear it shows.

The Major Grade Tiers, Poor Through Mint State

Here is the whole scale condensed into its named tiers, built from the published PCGS and NGC standards. Circulated grades measure wear. Mint State grades measure everything else: strike, luster, marks, and hairlines.

Two spots on this table do the heavy lifting at auction. The first is the AU to MS line. An AU58 shows only the slightest friction on its highest points and keeps nearly full luster; an MS60 has no wear at all but may be poorly struck and covered in heavy marks. A pretty AU58 can look better than a baggy MS60, and bidders know it. The second is the climb inside Mint State. From MS60 to MS70, no coin has any wear. What separates a 63 from a 65 is the count and placement of marks and hairlines, and whether they land in focal areas like a cheek or an open field. Those distinctions sound small on paper. On an invoice they are anything but.

What NGC and PCGS Certification Actually Certifies

When a coin comes back from NGC or PCGS in a sealed holder, the slab certifies two things. First, the coin is genuine: professional graders authenticated it before anything else happened. Second, the number on the label is the service’s professional opinion of the grade, applied against a published standard. You can read those standards yourself: PCGS publishes its full grading standards and NGC posts its grading scale with a line-by-line definition of every grade. The holder also carries a certification number you can verify on the service’s website, which is why certified coins trade sight-unseen at auction in a way raw coins never will.

The letters in front of the number describe how the coin was made, not how nice it is. MS means Mint State, a business strike made for circulation, and applies to grades 60 through 70. Proof coins, struck with specially prepared dies for collectors, carry PR at PCGS and PF at NGC. SP marks a Specimen, a hybrid that sits between the two. A Proof is not automatically better than a Mint State coin; it is a different product, graded on the same 70-point ladder.

Both services also flag the standouts. PCGS adds a plus to coins in the top 30% of their grade, on grades from XF45 through MS or PR68. NGC assigns its own plus to coins at the high end of their grade and a star to coins with exceptional eye appeal. And both services refuse straight grades to problem coins: a cleaned, artificially toned, or damaged coin comes back in a details holder, or not holdered at all. That refusal matters at auction. A details slab tells every bidder the coin has an issue, and the bidding prices it in.

One thing certification does not do: set the price. The slab settles what the coin is. What it is worth gets settled by bidders, every week, in sales like ours.

Why One Grade Point Can Double the Price at Auction

Rarity in coins is condition rarity. The mints struck common-date Morgan dollars by the tens of millions, so a worn one is easy to find and priced like it. The same coin surviving with full luster and clean surfaces is a different animal, and the population thins fast with every point above 60. Prices follow the thinning. In one of our recent sales, an 1897-O Morgan graded MS65 brought $5,500, while common circulated Morgans in the same session brought far less. An 1889-CC Morgan in PCGS MS62, a better date in a better grade, brought $47,500. Both results sit in our published closed catalogs, and you can browse our auction results to see the pattern repeat across series after series.

This is why one grade point can double a price, and why the hobby pays professionals to draw those lines. Between MS64 and MS65 on a scarce date, the difference is not cosmetic, it is the gap between two price brackets. It also cuts the other way: a coin bumping against a grade line from below, that AU58 with a gem’s look, can bring more than its grade suggests when two bidders trust their own eyes. Grade sets the market’s expectation. The coin itself, on the screen and under the lights, sets the last few bids.

Certified vs. Raw Coins at Auction

We sell both, every week. Certified lots carry the slab’s two guarantees, genuine and professionally graded, so they draw wider bidding, including from buyers who will never see the coin in hand. Raw coins, meaning coins no service has graded, trade on the catalog photos and your own judgment. That is not a defect, it is the opportunity half the room shows up for. A sharp eye can buy a raw coin at a circulated price and find an AU coin in the flip. It can also buy a cleaned coin at full price, which is the tuition the hobby charges for skipping the homework.

If you are bidding: price a raw coin against certified examples of the same date and grade range, then leave room for the unknown. Study the photos for hairlines, unnatural color, and rim problems, and call us with the lot number if you want a straight answer about what we see. Our rare coin auctions usually carry a mix of NGC and PCGS certified pieces alongside raw collector coins, so a single session gives you both markets to compare in real time.

If you are selling: do not grade everything. Submission fees eat a cheap coin whole, and common circulated material sells fine raw in group lots. The coins that justify certification are the better dates, the high-grade pieces, and anything that might be a key date in disguise, because the slab converts a maybe into a fact that bidders pay for. Before you spend a dollar on submissions, start with our consignment page or call and describe what you have. We will tell you which coins to grade, which to leave raw, and what both should bring. Then watch a few of our weekly coin auctions to see certified and raw lots cross the block, and keep the rest of the Learning Center handy for the vocabulary that comes up along the way.

Coin Grading Questions