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Free Tool

Card Centering Tool

Centering is the first thing a grader measures. Enter your card’s border widths and see your exact front centering and the highest PSA grade it could support — before you spend a cent on grading.

Measure the borders in any unit (mm, or pixels from a straight scan) — just be consistent.

Horizontal borders
Vertical borders
Centering supports up to
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Horizontal (L/R)
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Vertical (T/B)
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Worst axis
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Centering looks good? → Run the grading ROI

Centering is a ceiling — corners, edges, and surface still decide the final grade.

PSA, BGS & SGC centering tolerances (front)

Centering is the first thing a grader measures, and it sets a ceiling on the grade before corners, edges, or surface are even considered. The three major graders are close at the gem tier but not identical — BGS is the strictest and grades centering explicitly, while PSA and SGC fold it into the single number. These are the widely-cited front-centering thresholds. The tool above uses the PSA column.

Grade tierPSA (front)BGS (front)SGC (front)
Gem Mint (PSA/SGC 10, BGS 9.5)~55/45 or better50/50 – 55/45~55/45 or better
Pristine (BGS 10)—50/50 (front & back)~50/50 (SGC 10 Pristine)
Mint (9)~60/40~55/45 – 60/40~60/40
NM-MT (8 / 8.5)~65/35~60/40 – 65/35~65/35
NM (7)~70/30~65/35 – 70/30~70/30

Approximate, widely-cited front tolerances for comparison — each grader’s exact criteria can vary and centering is only one of four factors. Backs are graded far more leniently (see below).

Reading the ratio: what 55/45 actually means

A centering ratio is just how the border width splits between the two sides of one axis. The tool works out both axes and reports the worst one, because that’s the axis a grader keys on — a card that’s perfect top-to-bottom but 62/38 left-to-right is a 60/40 card, not a 55/45 one.

  • 50/50 — dead center. The border is identical on both sides. BGS Pristine territory.
  • 55/45 — the gem-mint line. One side is a hair wider but still inside PSA/SGC 10 tolerance. This is the number collectors mean by the “55/45 rule.”
  • 60/40 — a clean Mint 9. Visible off-center to a trained eye, but sharp.
  • 65/35 — an 8. The image is noticeably shifted; one border is nearly twice the other.
  • 70/30 and beyond — the card is off-center enough that the grade is capped at 7 or lower no matter how clean the corners are. This is where a lot of otherwise-mint modern rookies get held back.

Because both the left/right (edge-to-edge) and top/bottom axes are scored, a card can be perfectly edge-centered horizontally and still fail on the vertical axis — always measure all four borders, not just the two that look worst.

Front vs. back centering

Both are measured, but the front is the gate. Front centering is judged strictly (55/45 for a 10); the back is judged much more leniently — a 10 generally allows about 75/25 on the back. For most cards the front is what caps the grade, which is why this tool scores the front. The exception is BGS, which assigns a separate centering subgrade and weighs the back explicitly, so a badly off-center back can cost you a BGS 9.5 even with a gem front.

How to measure accurately

  • Scan straight-on at high resolution, or use calipers on the physical card. A tilted phone photo will lie to you.
  • Measure to the same reference on each side — typically the edge of the printed image (or the inner frame line) to the edge of the card.
  • Be consistent with units. Millimeters, or pixels off a flatbed scan — ratios are what matter, not the absolute numbers.
  • Check both axes. Enter left/right and top/bottom; the worst axis is the one that sets your ceiling.

Centering looks good — is it worth grading?

Centering is only a ceiling. Once your worst axis clears the tier you’re after, the grade still comes down to corners, edges, and surface — and to whether the graded copy sells for enough more than the raw card to justify the fee. Run those numbers with the free grading ROI calculator, and for where Antonelli’s cards actually sit on the value ladder, see the Kimi Antonelli card value guide and our collecting guide.

Frequently Asked Questions

How do I measure card centering?
Measure the white border on the left and right of the card’s image (horizontal), and the top and bottom borders (vertical). Use any unit — millimeters, or pixels from a straight-on scan — as long as you’re consistent. Enter all four and the tool converts them to a centering ratio like 55/45 and tells you the best PSA grade that centering allows.
What centering do you need for a PSA 10?
PSA’s Gem Mint 10 generally requires roughly 55/45 centering or better on the front (and about 75/25 or better on the back). PSA 9 allows about 60/40, PSA 8 about 65/35. Centering is only a ceiling, though — corners, edges, and surface still have to hold up for the card to actually hit that grade.
Does centering alone determine the grade?
No. Centering sets the maximum grade a card can earn, but corners, edges, and surface condition can pull it lower. A perfectly centered card with a soft corner won’t get a 10. Use this to rule cards out (bad centering caps the grade) and pair it with an honest look at the other three factors.
What is the 55/45 centering rule?
55/45 is the front-centering line for a gem-mint 10 at PSA and SGC: no side of the border can be more than 55% of the combined border width on either axis. 50/50 is dead-center; 55/45 means one side is slightly wider but still within Gem Mint tolerance. Past 55/45 you drop to a 9 (about 60/40), then an 8 (about 65/35). The tool scores the worst of your two axes against this rule.
Do PSA, BGS, and SGC use the same centering tolerances?
They’re close at the top but not identical. All three want roughly 55/45 or better on the front for their gem tier, but BGS is the strictest — a true BGS 10 Pristine wants 50/50 front and back, and BGS publishes a separate centering subgrade. PSA and SGC fold centering into the single number. The comparison table below lays out the widely-cited front tolerances side by side.
Is centering measured on the front or the back?
Both, but the front is the gate. Graders judge front centering strictly (55/45 for a 10) and the back much more leniently (a 10 generally allows about 75/25 on the back). A great front with a badly off-center back can still cost you the top grade at BGS, which grades the back explicitly — but for most cards the front is what caps you. This tool scores the front, where centering is judged hardest.