Grading & condition
Card Centering Calculator
Measure the four borders, in any unit you like, and this gives you the centering ratio each grading company reads off the card — plus the best grade that ratio can still earn. Centering is the only part of a grade you can check yourself with certainty, and it is the most common reason a card that looks flawless comes back a 9.
How centering is measured
A grader compares the two opposing borders and expresses the wider one as a percentage of
the pair. A card with a 2.4 mm left border and a 2.0 mm right border is
2.4 ÷ (2.4 + 2.0) = 54.5%, reported as 55/45. Both axes are
measured, and the worse of the two is the one that sets your ceiling — perfect top-to-bottom
centering does not rescue a card that is 70/30 left-to-right.
The back is graded to a looser standard than the front at every company, because back-centering was never controlled well in production. PSA allows 75/25 on the back of a card it will still grade Gem Mint 10.
Published centering tolerances
| Grade | PSA front | PSA back | BGS front | SGC front |
|---|---|---|---|---|
| 10 Gem Mint | 55/45 | 75/25 | 50/50–55/45 | 55/45 |
| 9.5 | — | — | 55/45–60/40 | — |
| 9 Mint | 60/40 | 90/10 | 60/40–65/35 | 60/40 |
| 8 NM-MT | 65/35 | 90/10 | 70/30–75/25 | 65/35 |
| 7 NM | 70/30 | 90/10 | 75/25–80/20 | 70/30 |
| 6 EX-MT | 80/20 | 90/10 | 80/20–85/15 | 80/20 |
| 5 EX | 85/15 | 90/10 | 85/15–90/10 | 85/15 |
| 4 and below | 90/10 | 90/10 | 90/10 | 90/10 |
Why this is worth doing before you pay
Centering is the only grading criterion with a published numeric threshold. Corners, edges and surface are judgement calls that vary between graders and between days; centering is a ruler. If your card measures 68/32 on the front, no grader will call it a 9, no matter how sharp the corners are — and knowing that before you spend $15 to $80 on the submission is the entire point.
The practical workflow: scan the card at 600 dpi, open it in any image editor, and read the border widths in pixels. Pixels are far more precise than a ruler on a 2.5-inch card, and because the formula is a ratio, no conversion is needed.
Where measurement goes wrong
- Measuring to the wrong line. Measure from the cut edge to the start of the image area, not to the edge of a coloured design element that is itself part of the artwork.
- Cards with no border. Full-bleed modern cards have no measurable border, so graders judge centering off the position of internal design elements. This calculator cannot help with those.
- Miscut versus off-centre. A card showing part of the neighbouring card is a miscut, which is a different defect and usually a hard cap regardless of ratio.
- Rounding. Graders work in bands, not decimals. A 55.4% measurement is 55/45 and passes; 55.6% rounds to 56/44 and does not.
Questions people ask about this
What centering do you need for a PSA 10?
A PSA Gem Mint 10 allows up to 55/45 on the front and 75/25 on the back. That means the wider of two opposing borders can be no more than 55% of the pair. A card at 56/44 on the front is capped at PSA 9 on centering alone, regardless of how clean the corners, edges and surface are.
How do you calculate card centering?
Divide the wider border by the sum of both opposing borders and multiply by 100. A 2.4 mm left border against a 2.0 mm right border gives 2.4 ÷ 4.4 = 54.5%, written as 55/45. Do this for left-right and top-bottom separately; the worse of the two results is the card's centering.
Is BGS centering stricter than PSA?
At the top of the scale, yes. BGS reserves a 10 centering subgrade for cards at 50/50 to 55/45 and has a 9.5 step that PSA does not, so a card PSA calls a 10 can register as a 9.5 at Beckett. Below that the two converge, and by the 6-to-8 range Beckett is marginally more forgiving.
Does back centering matter?
Less than the front, but it can still cap a grade. PSA allows 75/25 on the back of a Gem Mint 10 and 90/10 from Mint 9 downward — wide enough that most cards pass, but not all. Vintage cards from sheets that were cut carelessly are the usual casualties.
What unit should I measure in?
Any unit, because the result is a ratio. Pixels off a 600 dpi scan are the most accurate option available at home: a 2.5-inch card gives you 1,500 pixels of width to measure against, where a millimetre ruler gives you about 64 divisions. Just measure all four borders the same way.
Where these numbers come from
Rates on this page were last checked against the published price lists on . Grading companies change fees and pause tiers without notice — confirm the total on the submission form before you pay.
- PSA — grading standards — front and back centering tolerance per grade
- Beckett — grading scale and subgrades — BGS centering bands
- SGC — grading scale — SGC tolerance bands