Key points
- Grading assesses centring, corners, edges and surface, then encapsulates the card.
- PSA uses one overall 1-10 grade; BGS publishes four subgrades plus an overall.
- The slab protects the card and makes it easier to sell remotely.
- Grading does not make a common card valuable.
What a grade actually measures
A grader examines the card under controlled light and scores four attributes. Centring is the ratio of borders left to right and top to bottom. Corners are checked for softening and whitening. Edges are checked for chipping and rough cuts. Surface covers print defects, scratches, indentations and gloss.
The overall grade is not an average. On most scales the weakest attribute effectively caps the result, which is why a card with three perfect attributes and one soft corner does not reach the top of the scale.
The main grading companies
Four companies dominate. They differ in scale, presentation and market preference, and those preferences vary by category.
- PSA — a single 1-10 grade. The broadest market recognition, particularly for vintage and for football and basketball singles.
- BGS (Beckett) — four published subgrades plus an overall, with a black label reserved for four perfect 10 subgrades. Popular for modern chrome and autographs.
- SGC — a 1-10 scale in a distinctive black-matted holder. Strong reputation in vintage.
- CGC — a 1-10 scale, well established in adjacent collectables and increasingly used for trading cards.
Reading a label
Every slab carries a certificate number that can be checked on the grader's own website. That lookup confirms the card, the set, the grade and any qualifier, and it is the single most useful anti-fraud step a buyer can take before paying.
Qualifiers matter. A grade shown with OC (off-centre), ST (stain), MK (marked) or MC (miscut) means the card met the numeric standard in every respect except the flagged one, and it usually sells well below a clean grade at the same number.
Population reports
Each grading company publishes how many copies of a card it has graded and at what grades. This is the closest thing the hobby has to a public supply figure. A card with three thousand graded copies and four hundred at the top grade is a different asset to one with eleven graded copies and one at the top.
Populations only grow. A low population today is not a guarantee of scarcity tomorrow, particularly for a modern card that people are still submitting in volume.
Submitting from the UK
UK collectors submit either directly to a grader's international intake, or through a group submission run by a UK dealer or shop. Group submissions spread the postage and customs handling across many cards and are usually cheaper for a small number of cards.
Whichever route you use, photograph every card front and back before it leaves your hands, insure the parcel for the declared value, and expect turnaround measured in weeks or months rather than days.
Common questions
Does grading increase a card's value?
It increases the value of cards that grade well and are already in demand. A common base card in a slab is a common base card with a grading fee attached.
Can a graded card be regraded?
Yes, by cracking the slab and resubmitting, but the previous grade is a matter of public record via the certificate number and the new grade may be lower.
Which grader should a UK seller choose?
For most football, basketball and vintage singles PSA has the widest buyer recognition. For modern chrome and autographs where subgrades help tell the story, BGS is a common choice.