PSA Centering Calculator: How to Calculate 60/40 vs 55/45
How to calculate 60/40 vs 55/45 centering and what those ratios mean for your card.
Centering ratios like 60/40 and 55/45 get thrown around constantly in the hobby. Here's exactly what they mean and how to calculate them for any card.
What a Centering Ratio Actually Measures
A centering ratio compares the border width on one side of the card to the border on the opposite side. A perfectly centered card would be 50/50 — equal borders. The further from 50/50, the more off-center the card.
The Formula
Centering Ratio
Ratio = Left ÷ (Left + Right) × 100
Then repeat for Top ÷ (Top + Bottom).
Worked Example: 60/40
- Suppose the left border measures 3 mm and the right border measures 2 mm.
- Total horizontal border = 3 + 2 = 5 mm.
- Larger side: 3 ÷ 5 = 60%. Smaller side: 2 ÷ 5 = 40%.
- That's a 60/40 card on the left-right axis.
60/40 vs 55/45: Why It Matters
Those five percentage points are the line between Mint and Gem Mint for many cards — and a huge swing in value.
Do It on Both Axes
A card can be perfect left-to-right but off top-to-bottom. PSA considers the worse of the two, so always calculate both and judge by the weaker axis.
Skip the ruler
Measuring borders by hand is fiddly and error-prone. MintySlab detects the edges and computes both ratios automatically — no ruler, no math, no guesswork.
Quick Reference
- 50/50 — perfectly centered
- 55/45 — excellent, PSA 10 range
- 60/40 — good, PSA 9 range
- 70/30 and beyond — visibly off-center, grade-limiting
Stop guessing — let MintySlab measure centering for you. Scan Before You Slab.