Grading trading cards: how it works and when it is worth it

A graded card is sealed in a hard plastic case, usually called a slab, with a label showing a number from 1 to 10. That number is a professional opinion of the card's condition, and it can make the difference between a card being easy or hard to sell. Grading is not right for every card, though, and the costs add up quickly.

What grading services do

A grading company checks that a card is genuine, assesses its condition against a published standard, and seals it in a tamper-evident case with a label and a unique certification number. Most services let you look up that number on their website, which helps buyers confirm a slab is real. Several large companies operate internationally, and there are UK-based services too. Each has its own scale details, label style and reputation among collectors.

The 1 to 10 scale

Most services use a ten-point scale. A 10 is typically described as gem mint: essentially flawless to the naked eye and under magnification. 9 is mint with a very minor flaw, and the grades step down through near mint and excellent to poor. Some services use half points, and some give separate subgrades for the four areas below. A card that is genuine but altered, trimmed or recoloured is usually returned ungraded or marked as such.

The four things graders look at

• Centring. How evenly the printed image sits within the borders, front and back. Slightly off-centre printing is common straight from the pack and can cap a grade even on an untouched card.
• Corners. Sharp, square corners score well; rounding, softness or tiny dings lower the grade.
• Edges. Look for white flecks ("whitening") on coloured borders, chipping or roughness from the cutting process.
• Surface. Scratches on holo areas, print lines, dents, fingerprints and indentations. Tilt the card under a bright light to see them.

Before you submit

Inspect each card under a lamp with a loupe or phone camera. Be honest: if you can see whitening or a scratch, a grader will too. Handle cards with clean, dry hands, sleeve them in a fresh penny sleeve and place them in the holder the service asks for, often a semi-rigid card saver. Never try to "fix" a card by pressing, cleaning with chemicals or trimming. Alterations are usually detected and the card is rejected.

Read the service's current submission rules carefully. Fees normally depend on the declared value and turnaround speed, and you also pay for insured postage both ways. Sending cards abroad can add customs paperwork and import charges on the way back.

When is grading worth it?

Grading tends to make sense when a card is both desirable and in very good condition, when you plan to sell and buyers expect authentication, or when a card has strong personal value and you want it protected and verified. It rarely makes sense for common cards, for cards with obvious wear, or simply because a card is old. Add up fees, postage and waiting time, then compare that to what the card means to you. Many collectors grade only a handful of favourites and keep the rest in binders.

Whether or not you grade, good storage protects value. See our guide to protecting trading cards.

General information only. Product contents, rules and policies change, so check the current details with the manufacturer or seller. Brand names are trademarks of their owners; this guide is independent and sells nothing.