Card centering, explained
Centering compares the border widths on opposite sides of a card. It’s one of the few grading factors you can measure exactly before you submit.
What “55/45” means
Measure the border on the left and on the right. Add them together, then work out what share of the total each side is. If the left border is 2.2 mm and the right is 1.8 mm, the total is 4 mm, and the split is 55/45. Do the same for top and bottom. The worse of the two splits is the one that counts.
A perfectly centered card is 50/50. The further from 50/50, the lower the best possible grade.
What each PSA grade allows
PSA publishes centering limits for each grade. As cited in collector guides to PSA’s grading standards:
| Grade | Front | Back |
|---|---|---|
| Gem Mint 10 | about 55/45 | about 75/25 |
| Mint 9 | about 60/40 | about 90/10 |
| NM-MT 8 | about 65/35 | about 90/10 |
| NM 7 | about 70/30 | about 90/10 |
PSA graders can allow some leeway for eye appeal, and other companies use their own standards. Check the grading company’s current published standards before relying on these.
Notice how much stricter the front is. A back at 70/30 can still be a 10; a front at 60/40 can’t.
Measuring from a photo
- Shoot straight on. Lay the card flat and hold the phone directly above it. Any tilt makes the near border look bigger.
- Take it out of the sleeve if you can, or at least avoid glare across the borders.
- Use a plain, contrasting background so the card’s outer edge is easy to see.
- Find the inner border carefully. On most cards it’s the frame line around the artwork, not the edge of the art itself.
What centering can’t tell you
Good centering only sets a ceiling. Corners, edges, and surface scratches or print lines can still pull the grade below it. If centering already rules out a 10, run the profit math on a 9 or lower before you decide to submit.