Centering standards

Published tolerances and the centering ceiling

PSA requires approximately 55/45 on the front and 75/25 on the back for a PSA 10. CGC Gem Mint 10 uses approximately 55/45 on the front and 75/25 on the back. These are centering requirements; corners, edges and surface are assessed separately.

The tables below show the thresholds used by the calculator. Official means a published numerical rule. Interpreted means a rule translated into a measurable limit or an incomplete published scale. Approximate means a working estimate; it is not an official numerical promise.

Rounding and the meaning of 50/50

Ratios compare opposing printed border widths. A major ratio of 55 means 55/45. The app rounds the major ratio to the nearest whole point before comparing it with the table: 55.49 passes a 55/45 limit, while 55.50 does not. This is an app convention, not a published rounding guarantee from a grader.

A stated 50/50 requirement is modeled as approximately 52/48. This two-point tolerance is an interpretation and is marked as such. Pristine centering still depends on the grader’s judgment.

Beckett uses two front axes

The BGS front centering subgrade uses a tight axis and a loose axis. The app interprets BGS 9.5 as one axis within approximately 52/48 and the other within 55/45. Both axes must pass their respective limits. BGS 9 allows both front axes within 55/45.

Beckett’s official grading-scale URL currently redirects European visitors to a maintenance page. BGS rules are marked interpreted where appropriate; lower steps are approximate. The output is a centering subgrade ceiling, not an overall BGS grade.

Front and reverse limits

For a two-sided measurement, Centering Lab uses the lower centering ceiling from the front and back. A CGC reverse within 75/25 is labeled Gem Mint; passing that reverse limit does not block a Pristine ceiling on the front.

SGC has no separate numerical reverse limit in this model. Only the front limits the SGC result, and the displayed SGC bands are approximate. This does not mean that SGC ignores the reverse during grading.

Why TAG is excluded

TAG uses an automated process with card-specific assessment. Centering Lab does not have a sufficiently clear, reproducible public table to model its thresholds. TAG is therefore excluded.

Last verified: October 2026. A source URL being available does not establish that every interpreted or approximate threshold is official. When a source is temporarily unavailable, that limitation is shown.

PSA

PSA uses the most off-center part. It may apply the OC qualifier instead; eye-appeal exceptions are not modeled.

PSA · Source

Last verified: October 2026 · official

BGS

This is the centering subgrade. Front: one tight axis and one loose axis. 50/50 is interpreted as ≤52/48. Lower bands are approximate.

BGS · Source

Last verified: October 2026 · interpreted · Source unavailable from this region

CGC

50/50 is interpreted as ≤52/48. Below 10, CGC publishes these numerical tolerances for sports and non-sports; here they are a TCG reference.

CGC · Source

Last verified: October 2026 · interpreted

SGC

Front thresholds are approximate. SGC does not publish back tolerances, so the back does not limit the ceiling.

SGC · Source · Secondary source

Last verified: October 2026 · approximate