How coin grading works

A coin's grade is a shorthand for how much of its original design and surface survives. Collectors use the 1 to 70 Sheldon scale, and the difference of a few points can matter more than the date. This guide explains the scale, what graders actually look at, and how problem coins are handled.

By Changes Hands Research · Updated Nov 3, 2026 · 6 min read

Why grade matters

Two coins with the same date and mint mark can be worlds apart. One spent decades in pockets and cash drawers and is worn nearly smooth; the other went from the mint into a bank bag and still has the frosty surface it was struck with. Collectors pay for that difference, so they need a shared vocabulary to describe it. Grading is that vocabulary.

A grade is an opinion, not a measurement. Experienced graders agree most of the time, and they agree more often at the low end of the scale, where wear is easy to see, than at the top, where a single point can turn on a few faint marks. Keep that in mind whenever you read a number on a holder.

Where the 1 to 70 scale came from

The numbers come from Dr. William H. Sheldon, who published Penny Whimsy in 1949. Sheldon was studying early American large cents, and he proposed a numerical scale running from 1 to 70 alongside a formula that tied the number to value. The formula did not survive; the scale did. Over the following decades the American Numismatic Association adopted it in its grading standards, and the major third-party grading services built their businesses on it.

Today every serious US coin market speaks Sheldon. An auction catalog, a dealer price list and a PCGS or NGC holder all use the same numbers, which is what makes grades comparable across sellers.

The scale, band by band

Only certain numbers are used in practice. Below 60 the scale measures wear; from 60 up it measures the quality of a coin that has no wear at all.

Poor (1) and Fair (2): barely identifiable as to type, often with the date partly gone.
About Good (3): heavily worn, with the rims worn into the lettering, but the date can still be identified.
Good (4 and 6): the design is outlined and the date and lettering are readable, but there is little interior detail.
Very Good (8 and 10): well worn, but major features are clear and some interior detail shows.
Fine (12 and 15): moderate, even wear. Key details such as LIBERTY on an Indian cent or the horn on a Buffalo nickel are visible.
Very Fine (20 to 35): light to moderate wear on the high points; most fine detail is sharp.
Extremely Fine, written XF or EF (40 and 45): light wear on the highest points only, sometimes with traces of mint luster.
About Uncirculated (50 to 58): just a trace of friction on the high points, with most of the luster intact.
Mint State (60 to 70): no wear. The grade within Mint State depends on contact marks, luster, strike and eye appeal. MS70 means no post-production imperfections visible at 5x magnification.
Proof (PR or PF 60 to 70): the same numbers applied to proof coins, which are struck with special dies and planchets for collectors.

What a grader actually looks at

Wear comes first for circulated coins. Every design has high points that touch other coins and fingers first: the cheek and hair above the ear on most portraits, the breast feathers on most eagles. A grader checks those spots for flattened metal and broken luster, then works outward to see how far the wear has spread. Each series has its own diagnostics. On a Mercury dime the bands across the fasces tell you most of what you need; on a Walking Liberty half it is the skirt lines and Liberty's hand. Our series pages list the diagnostics for each coin we trade.

Strike describes how fully the dies pressed the design into the metal. A weakly struck coin can look worn when it is not; the difference is that a weak strike leaves the original mint surface in place, while wear replaces it with smooth or grainy metal. Many 1920s Buffalo nickels and New Orleans Morgan dollars are known for soft strikes, and graders allow for it.

Luster is the cartwheel of light that rotates across a fresh coin as you tilt it under a single lamp. It is created by the flow of metal during striking and it never comes back once it is broken. That is why luster matters so much at the top of the scale, and why cleaning is so destructive.

Surface preservation and eye appeal cover everything else: contact marks from bags and counting machines, hairlines, spots, and the overall look of the coin at arm's length. Attractive natural toning can help; dark, blotchy or artificial color hurts.

Problem coins and details grades

A coin that has been cleaned, polished, scratched, bent, holed, corroded or tooled does not get a normal number. Instead it receives what the trade calls a details grade: the wear level it would have, plus a note on the problem. NGC labels these coins Details, for example XF Details, Improperly Cleaned. PCGS labels them Genuine with a similar description. Details coins sell at a meaningful discount to problem-free coins of the same wear, and some buyers avoid them entirely.

Cleaning is the most common problem by far. Rubbing a coin, dipping it in jewelry cleaner or brushing it leaves fine parallel hairlines and an unnatural brightness that experienced eyes spot immediately. The single most useful piece of advice for anyone who inherits coins is to leave them alone.

Who grades coins

PCGS and NGC are the two services whose grades the market prices most consistently. They authenticate the coin, assign a grade, and seal it in a tamper-evident plastic holder, the slab, with a certificate number you can look up online. Our guide to PCGS, NGC and CAC covers how they compare.

Third-party grading has a cost, and for a common worn coin the fee can exceed the coin's value. That is why Changes Hands house-grades low-value raw coins under its own published standard, the Changes Hands Grading Standard (CHGS). Two trained graders grade each coin independently and blind; if they are one band apart, the lower band stands. CHGS uses eight bands, from About Good to Uncirculated, each mapped to a Sheldon range, and every coin in a band must meet all of that band's requirements on both sides. A CHGS band is a Changes Hands service grade, not a PCGS or NGC grade.

Learning to grade yourself

You do not need to grade like a professional to buy well, but a little practice pays off quickly. Pick one series and study it.

Use a 5x loupe and a single bright lamp, not overhead or diffuse light, which hides hairlines and wear.
Hold coins by the edge over a soft surface. Tilt and rotate them to watch the luster move.
Compare raw coins against certified examples of known grade, ideally side by side.
Learn the high points and diagnostics of your series before anything else.
Grade both sides. The lower side usually sets the grade.
When you are unsure between two grades, assume the lower one. Sellers rarely lose money that way.

Frequently asked questions

What does MS65 mean on a coin?

MS65 means Mint State 65: a coin with no wear, strong luster and only a few minor contact marks, none of them in prominent places. It is often called Gem Uncirculated. Coins graded MS65 and higher are noticeably scarcer than MS63 or MS64 examples for most classic series.

Is AU better than XF?

Yes. About Uncirculated (50 to 58) sits above Extremely Fine (40 to 45). An AU coin shows only a trace of friction on the highest points and keeps most of its luster, while an XF coin has light but definite wear on the high points.

Can a coin's grade change?

The coin itself only changes if it is handled, cleaned or damaged. Its assigned grade can change if it is resubmitted, because grading is an opinion. A slabbed coin sent back for review may come back the same, higher or lower, so resubmitting always carries some risk.

Why are some numbers, like 7 or 11, never used?

The scale is continuous on paper, but grading services only assign the numbers that collectors can reliably tell apart. Between 4 and 60 that means a handful of steps: 4, 6, 8, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 53, 55 and 58. Every whole number from 60 to 70 is used.

Does cleaning a coin increase its grade?

No. Cleaning removes metal and destroys original luster. A cleaned coin receives a details grade instead of a number and is worth less than an uncleaned coin with the same wear.