What Are Subgrades in Trading Card Grading?

Subgrades are the four separate scores a grading house assigns to a card's centering, corners, edges, and surface axes, each ranging from 1 to 10 in half-point increments. BGS and CGC display subgrades prominently on the slab label; PSA does not publish subgrades. Subgrades let buyers see why a card received a given composite grade.

Detailed explanation

BGS pioneered the four-axis subgrade system: centering, corners, edges, surface, each scored independently from 1.0 to 10 in 0.5-point steps. The composite grade is then derived from a published formula that incorporates floors and weights — a 9.5 floor on all four axes yields BGS 9.5; three 10s and one 9.5 yields BGS 9.5; four 10s yields BGS 10 Pristine; four 10s with no axis below 10 qualifies for Black Label.

CGC adopted a similar four-axis system when entering TCG. PSA still publishes only a composite grade — a deliberate market choice that emphasizes simplicity but obscures the underlying defect pattern. A PSA 9 could have weak centering and perfect surface, or strong centering and a faint corner ding; the buyer cannot tell without inspecting the card.

Common misconception: subgrades and the composite grade always agree arithmetically. They do not — there is a published formula at BGS, but it is not a pure mean. The lowest subgrade floor matters more than the average.

How AuraGrade measures it

AuraGrade reports all four subgrades (CTR, COR, EDG, SUR) in every grading report regardless of whether the user plans to submit to PSA, BGS, or CGC. The subgrade breakdown is more diagnostically useful than the composite alone.

Worked example

Two cards both receive BGS 9.5. Card A subgrades 9.5/9.5/9.5/9.5 — uniform, no axis weaker than another. Card B subgrades 8.5/10/10/10 — composite math still hits 9.5, but centering 8.5 means the card looks visibly off-center. Market prices Card A higher despite identical composite.