Sports Card Grading 101: The Definitive Tutorial

sports card grading

Understanding how to grade a sports card can be an invaluable tool for both new collectors and grizzled veterans of the hobby.

While most turn to third party card grading services (such as PSA and SGC), knowing what a raw card will earn for a grade is important for collectors.

In this piece, we discuss some of the pros and cons of the third party grading companies, while offering collectors a lesson on professional grading.

We hope this resource will provide everything you need to view cards just as the professionals do.

This knowledge will help when spotting raw cards for sale and allowing you to come up with an expected grade on the spot.

Card Grades

The grades for cards are as follows, from best to worst.

Gem Mint, Mint, Near Mint to Mint, Near Mint, Excellent-Mint, Excellent, Very Good, Good, Fair, Poor

Note that this is a generic classification system that is standard throughout the industry.  As we will explore in later sections, the third party grading companies have their own guidelines, but the actual grades are consistent across the grading companies.

Also, it’s important to note that the age of cards makes no difference in card grading!  A 1909 T206 card that is graded as Mint is held up to the same standards as a 2018 Topps card.  It’s a common misconception, but Mint is Mint and Poor is Poor, no matter the age of the card.

Key Characteristics of Grading


Centering is one of the key inputs to evaluating a card’s grade.  For some collectors, a card with near perfect centering is an absolute necessity, while some are willing to overlook centering in hopes of a card with pristine corners and little surface wear.  Whatever the case, centering is an important part of the grading process.  One can typically eyeball a cards’s overall centering.  It might be hard sometimes to tell if a card has perfect 50/50 centering, but it’s fairly easy to tell is something is quite off-center.


Mike Trout rookie with perfect 50/50 centering

Centering is actually a mathematical process, and the professional graders are actually measuring the distance of the outside border to the edge of the card on the top and bottom and left and right.  If the distance is exactly the same for all four measurements, a card is considered to have perfect centering.

Here’s a great little spreadsheet that someone from the Collector’s Universe built to help in calculating the actual centering percentages.

It’s somewhat simple: measure the top and bottom borders in your preferred unit (mm, inches, whatever), add the two and then divide the top border measurement by the sum.  So here’s a Jordan Rookie with some clear centering issues (it actually received a Mint (9) rating from PSA but with an OC or off-center qualifier).  According to PSA, a card that gets a Mint (9) rating from them has to have centering of 60/40 to 65/35 on the front.  If we measure the left and right borders, we find that this Jordan card actually has 70/30 centering.  So, even though it met all of the requirements of a Mint card, it’s centering led it to receive a 9 (Mint) grade with an OC (or off-center) qualifier.


Jordan rookie with OC (off center) qualifier

Note that the different grading companies have slightly different standards for centering.  PSA is slightly more lenient versus SGC.


A card that is considered “Gem Mint” must have four perfectly sharp corners and is a general standard across the grading companies.  What you and I think might be perfect corners, might not cut the grade with PSA or SGC, as the graders are looking at the card under magnification in order to get a close look at the card.  Any slight imperfection on one corner will move you down the grading scale, while multiple corner issues will move you even further down the scale.  Cards that are graded Fair or Poor typically have severely rounded corners.


Most collector’s don’t normally think of a cards surface when considering a card’s grade, but this in an important factor.  A perfect card with sharp corners yet with some fingerprints or dirt on the surface will never earn a Gem-Mint rating.  As we discuss later, using a jewelers loupe and/or a blacklight can also help get your eyes on some other unidentifiable surface issues that your naked eye can’t pickup.

Surface problems can come in all kinds of forms, but some of the more common issues that will downgrade a card’s grade are wax stains, print defects, focus imperfections, scratches, scuffing , and creases.   Some surface issues might be potentially cleaned from the card, like dirt or fingerprints, while the others are unfortunately just something you’ll have to deal with.   Lower graded cards will have these problems in increasing numbers and severity.   As we also note later, PSA has its own ‘qualifiers’ such as ‘ST’ (or stain) that will be added on to a cards typical grade.


The edges (or borders) of a card is also an important factor when considering a card’s overall grade.  A card in Gem Mint or even Mint condition should have sharp edges with no signs of chipping.  Sometimes it can be hard to see problems on a card’s borders with your naked eye, thus a loupe or other type of magnifying glass is needed in order to get a closer look at the card.   Cards in lower grades typically have significant border wear with potentially chipped edges on the card.

The Card Grading Companies

Let’s take a quick look at the card grading companies.  Here is an overview of all of the major graders you need to be concerned with:

Professional Sports Authenticator (PSA)

PSA is the largest and most highly respected card grader on the market.   Many might argue the point, but PSA graded cards tend to carry a better premium in the resale market versus other third party graders.

Cards are graded on a 10 point scale from 1 through 10, with 10 (Gem-Mint) being the best.  Cards that are graded as ‘Authentic’ are known to be genuine, but because of an alteration or other defect, the grader was unable to provide a numbered grade.

PSA also has ‘qualifiers’ which can be added to a numbered grade—such as OC (off-center) or ST (stain).  According to PSA, a “Qualifier” is a term used when “an item meets all of the criteria for a particular grade but may still have one significant flaw”.

List of PSA Qualifiers
OC – Off-Center
ST – Staining
PD – Print Defect
OF – Out of Focus
MK – Marks
MC – Miscut

Qualifiers tend to bring a card down on average one to two grade levels in the resale market–for example a PSA 8 card with an OC qualifier would likely sell for what a PSA 6 or PSA 7 card would go for.   Note that when submitting cards for grading, one can request a grade with ‘no-qualifiers’.

Aaron rookie with OC or off center qualifier from PSA

One of the reasons for PSA’s market dominance, is the well documented population reports for graded cards, along with the impressive set registry, which allows collectors to submit and track their collections on PSA’s website.

Costs for submission vary but starts at $20 for regular card grading.  Due to popularity of card grading in recent years, turnaround times on submissions has been severely impacted.  PSA is a division of Collector’s Universe (CLCT), a publicly traded company.

PSA has been on a remarkable rise since 1991, a year which marked a tumultuous time in the grading company’s early years; allegations arose that it knowingly ignored an obvious trimmed 1909 T206 Honus Wagner card.  Even ignoring that black mark on PSA’s history, I can assure you of one thing–the third party card graders are not always right!  You can read an example of this in our lengthy piece on strip cards.


T206 Wagner which was later learned to have been trimmed

Sportscard Guaranty Company (SGC)

If PSA is numero uno in the grading community, then SGC is a close second.  SGC is popular with some vintage collectors who prefer the black inserts used in the SGC card holders.  Still, PSA clearly has the edge as the hobby’s favorite and is the preferred company to use for maximizing resale value.

As for quality, SGC has always been very consistent with their grading, maybe even with a better reputation versus PSA in this regard.  But in the end, all of the grading companies are going to make mistakes; they are after all only humans.  The days of Artificial Intelligence and algorithmic grading aren’t here (YET) so we have to live with the flaws that human grading brings to the table.


There will always be cards that appear under or over graded, and in the former, most just chalk it up to the grader having a bad day. I WISH that there was more uniformity among third party graders, but until those bots start grading cards, it is what it is.

Side note, i saw someone in a forum i visit frequently mention this about the inconsistency with grading and I thought it was spot on.  THE ROBOTS ARE COMING (maybe?)

The grading industry is long overdue for a major overhaul. I hope that whatever technology will be used corrects some or all of the current problems. I really don’t want to hear about the subjectivity of grading. I want to hear about a system that grades cards correctly and will deliver that same grade no matter how many times a card is reviewed. I don’t want to hear stories about cards being submitted three times and getting three different grades. If it can’t be done right, then it shouldn’t be done at all.

BIG NOTE that SGC has recently moved to a new grading system!

From herein on in, they are only utilizing the 0 to 10 grading system that PSA uses.

Previously they used to include their 0 to 100 grade and the equivalent PSA 0 to 10 grade (see Ripken rookie card above for an example of this).  Now it will only be a 0 to 10 rating.  In addition, they went from their custom forest green color to new black bold lettering (see 75 Topps Ryan below).

I can tell you that personally I don’t like it, and most in the hobby don’t either.  I think the numbering grade change is a good one, but the color change just completely changes their identity.   Note that SGC is also introducing a new scanned registry which could be a game changer, but it all comes down to execution and I worry about SGC’s ability to do this effectively.


Beckett Vintage Grading (BVG)

I haven’t used Beckett as much as I have SGC and PSA, but in my experience the grading consistency is quite good.  The problem being that PSA and SGC tend to be more widely utilized with vintage cards, thus leading Beckett to be more of a lower tier grader in the vintage collecting world.

In addition, Beckett itself has three different grading subsidiaries: Beckett Grading Services (BGS) for cards from 1981 to present, Beckett Vintage Grading (BVG) for pre 1981 cards, and then Beckett Collectors Club Grading (BCCG) which is a lower tier grading level that Beckett uses and is generally not well regarded.

For vintage collectors, I wouldn’t really bother with any of the Beckett grading services.  I know some that use BVG for vintage card grading, but typically PSA or SGC will generate better returns.  In addition, I know someone who just waited over a year to receive some card submissions back from Beckett.  No thanks.

PSA VS SGC Centering Differences

PSA Grade
PSA Guidelines
SGC Grade
SGC Guidelines
Gem-Mint (10)
55/45 to 60/40 percent on the front, 75/25 on back
Gem-Mint (10)
55/45 or Better
Mint (9)
60/40 to 65/35 percent on the front, 90/10 on back
Mint (9)
60/40 or Better
Near Mint-Mint (8)
65/35 to 70/30 to percent on the front, 90/10 on back
Near Mint-Mint (8)
65/35 or Better
Near Mint (7)
70/30 to 75/25 to percent on the front, 90/10 on back
Near Mint (7)
70/30 or Better
Excellent-Mint (6)
80/20 percent on the front, 90/10 on back
Excellent-Mint (6)
75/25 or Better
Excellent (5)
85/15 percent on the front, 90/10 on back
Excellent (5)
80/20 or Better
Very Good-Excellent (4)
85/15 percent on the front, 90/10 on back
Very Good-Excellent (4)
85/15 or Better
Very Good (3)
90/10 percent on the front, 90/10 on back
Very Good (3)
90/10 or Better
Good (2)
90/10 percent on the front, 90/10 on back
Good (2)
90/10 or Better
Poor (1)
Any centering is allowed
Poor (1)
Any centering is allowed

A Visual Representation of Card Grades

  • Gem Mt (PSA 10, sgg 98)
  • MINT (PSA 9, SGC 96)
  • Nm-mt (PSA 8, sGC 88)
  • NM (PSA 7, SGC 84)
  • Ex-mt (PSA 6, SGC 80)
  • EX (PSA 5, SGC 60)
  • VG-EX (PSA 4, SGC 50)
  • VG (PSA 3, SGC 40)
  • GOOD (PSA 2, SGC 30)
  • FAIR (PSA 1.5, SGC 20)
  • POOR (PSA 1, SGC 10)

According to PSA, a grade of PSA 4 (Very Good – Excellent) means that a card’s corners may be slightly rounded. Surface wear is also noticeable but modest. May have light scuffing or light scratches. Some original gloss will be retained. Borders may be slightly off-white. A light crease may be visible. Centering must be 85/15 or better on the front and 90/10 or better on the back.

SGC’s equivalent for a PSA 4 is an SGC 50, with criteria mostly the same, although SGC notes centering must be 85/15 or better.

Below is a PSA 4 card of the GREAT ONE, 1979-1980 Topps Rookie Card.  There is certainly some corner and border wear and those corners are lot more rounded than any of the higher grade cards we’ve examined so far.   Other than that, the card overall is in pretty decent shape.

gretzky rookie


How To Submit Cards for Grading

Each company has their own requests for submitting cards to be graded.  I highly suggest reading all of the guidelines before submitting to each respective grader.  We will provide some more tips and advice on this at a later date.

PSA Grading Submissions:

SGC Grading Submissions:

BVG Grading Submissions:

Tools Needed To Become An Expert Card Grader

Grademaster Centering Tool (or just a Ruler)

First, you don’t NEED this, as I noted previously, you can just measure the borders and use this spreadsheet to help calculate the percentages.  But I have heard good things about this Grademaster tool so it seems really helpful and thought I would give it a plug here.  I’ve also heard of some people that use a  sewer’s Omnigrid, which is basically a plastic measuring grid. So either one is totally not necessary, as as ruler might be everything you need.

Jewelers Magnifying Loupe

I bought one of these from eBay and its just like what jewelers use and its only $5–it has an LED light and magnifies things up to 60x their size.  Good thing is that it’s portable, so if you’re going to a store or your local card show you can bring it along for the ride.

Microfiber Cloth

Surfaces are one of the key inputs to evaluating a card grade, so if the surface of the card is dirty or has fingerprints, it will receive a lower grade.  Carefully wiping the card clean with a microfiber cloth such as these can help avoid an unnecessary low grade due to a dirty surface.

Note that I also really liked this discussion on the Beckett forum about doing your own card grading.  They also discuss getting a blacklight, which can be very helpful in looking at surface issues along with helping identify if you might have a reprint/fake card on your hands.  I don’t own a blacklight (yet) but have my eyes on one, as I’ve run across a bunch of reprints that would be much easier to identify with a blacklight.