ACE Grading Centering Standards: Exact Tolerances for ACE 10 / 9.5 / 9 [2026]

What ACE Grading Considers Centering

ACE Grading measures centering as the ratio of the narrower border to the wider border on each axis (left-right and top-bottom) of the card. Perfect centering is 50/50, meaning the borders are exactly equal on both sides. A ratio of 60/40 means the wider border is 50% wider than the narrower border. ACE measures centering on both the front and the back of every card — and both must meet the grade's tolerance.

Unlike PSA, ACE publishes the measured centering ratio on each graded card's online certificate. This transparency matters when reselling: buyers can verify the actual centering instead of trusting only the overall grade.

Front Centering Tolerances per Grade

Both axes are measured independently — the worse of the two sets the centering grade. So an ACE 10 candidate must hit 50/50 ±2% on both left-right and top-bottom.

Back Centering Tolerances per Grade

The single biggest blind spot for submitters is back centering. Most collectors carefully evaluate the front, then forget the back exists. ACE measures it and enforces a maximum:

If the back centering is worse than the front-grade threshold, the back caps the overall grade. A card with 50/50 front centering and 70/30 back centering grades ACE 9 maximum.

How ACE Measures Centering at Submission

ACE's centering measurement process combines a calibrated scanner with a human-reviewer pass. The card is scanned at high resolution (typically 600 DPI), then software measures the border widths on each axis. A human grader spot-checks the measurement before the final centering tolerance is assigned.

This means ACE's centering measurement is reproducible — submit the same card twice, and you get the same centering ratio. PSA, by contrast, uses a less standardized centering review and is more variable on cards near a tolerance boundary.

The bevel and edge of the card are not counted as part of the border. ACE measures from the inside of the colored border (or the printed edge in borderless designs) to the corresponding inside edge on the opposite side.

Comparing ACE Centering to PSA, BGS, CGC and SGC

ACE is the centering-strict end of the spectrum:

Two practical takeaways: (1) PSA is materially more forgiving than ACE on both front and back centering, which is why a card that grades PSA 10 commonly grades ACE 9 or 9.5 on cross-submission. (2) ACE 10 and CGC Pristine 10 are roughly equivalent in centering strictness, with BGS Black Label slightly tighter on the back.

Why ACE's Centering Rules Are Tighter

ACE's positioning in the grading market is "the centering-strict grade." The premise: collectors of centering-sensitive cards (Pokemon Charizard 1st edition, Magic: The Gathering Black Lotus, vintage sports rookies where centering is the dominant value driver) want a grading service that takes centering more seriously than PSA does. ACE's ratings reflect that positioning.

This makes ACE 10s rarer — and therefore more valuable — for cards where centering is the differentiator. For cards where centering is not the bottleneck (heavily textured, holographic, or signature cards where surface and edges dominate), ACE's strict centering rule offers less of a value premium over PSA.

What ACE Rejects for Centering

The most common centering rejections at ACE:

• Front 53/47 with 50/50 expectation — outside the ±2% tolerance for ACE 10, gets ACE 9.5
• Back centering 65/35 on a card that has perfect front centering — caps the overall grade at ACE 9.5 regardless of front
• Print shift mistaken for centering — if the entire image is shifted on the card stock, ACE treats the shift as a centering defect, not a print error
• Off-cut cards — ACE does not exempt off-cut printing errors from the centering rule. A 1990s Topps card with a known production-run off-cut still gets centering-measured against the spec
• Borderless cards — measured from printed-edge to printed-edge; bleed area counts

How to Evaluate Your Card's Centering Before Submitting

Three approaches, ordered by reliability:

1. Calipers + ruler — measure each border with a 0.1 mm caliper on a flat surface, then compute the ratio. Most accurate, slowest.
2. Centering tool overlay — print a transparent centering grid (free templates available) and lay it over the card. Quick, ±2-3% accuracy.
3. AI photo analysis — upload a front + back photo to a tool like GradingMetric, which detects the card edges and the border widths automatically. ±1-2% accuracy on well-lit photos, gives you per-grade ACE / PSA / BGS / CGC / SGC probabilities in one shot.

If centering is the deciding factor between paying $20-50 for ACE submission or holding the card raw, the AI-prediction route is the cheapest way to validate before committing.

Can ACE Grades Cross to PSA or BGS?

Yes — collectors regularly cross-grade ACE cards to PSA. Two paths:

• Crack and resubmit — remove the card from the ACE slab and submit raw to PSA. Fastest, but the card's ACE history is lost.
• PSA CrossOver service — PSA grades the card in the ACE slab without cracking. Available for ACE, BGS, CGC and SGC slabs. PSA only awards the cross if the card meets the requested PSA grade.

Worth noting: cross-grading a PSA 10 to ACE almost always results in ACE 9 or 9.5 due to the centering rule. Cross-grading an ACE 10 to PSA usually maintains PSA 10 because PSA's centering tolerance is looser.

Predict Your ACE Grade With AI

The GradingMetric AI is calibrated on 24,000+ real grading outcomes including ACE submissions, and reports a centering measurement plus per-grade ACE probability matrix for any card you upload. You see the front + back centering ratio, the ACE 10 probability, and the side-by-side probability for PSA, BGS, CGC and SGC — so you can pick the Grader Fit that maximizes your card's expected value.

The first two predictions are free. Try it on your best card before paying for ACE submission. For the full ACE landing with fees and scale breakdown, see ACE card grading. For the head-to-head with PSA, see PSA vs ACE.