The Short Answer
- Centering is measured as a ratio of border widths, not a visual guess.
- PSA requires 55/45 or better for Gem Mint 10. BGS requires 50/50 or 55/45 for Pristine 10.
- Use a clear ruler or centering gauge in millimeters for precise measurement.
- Left/right centering and top/bottom centering are evaluated independently. The worse of the two determines the centering grade.
What Is Card Centering?
Card centering measures how evenly the printed image is positioned within the card's borders. A perfectly centered card has equal borders on all four sides. Centering is the most objective grading criterion because it can be measured with a ruler rather than judged by eye.
According to PSA's published grading standards, centering accounts for approximately 20% of the overall grade. A card with perfect corners, edges, and surface can still drop to a 9 or 8 if its centering is off.
How to Measure Centering
Follow this exact method used by professional graders:
- Measure the left border in millimeters with a clear ruler or acrylic centering gauge.
- Measure the right border in millimeters.
- Calculate the ratio: Divide the larger border by the total border width (left + right).
- Repeat for top and bottom borders.
- The higher ratio (left/right or top/bottom) determines the centering grade.
Example: Left = 2.5mm, Right = 2.0mm. Total = 4.5mm. Ratio = 2.5 ÷ 4.5 = 0.556 (55.6%). This card fails PSA 10 centering standards.
Company Centering Standards
| Company | Gem Mint Centering | Mint Centering |
|---|---|---|
| PSA | 55/45 or better | 60/40 or better |
| BGS | 50/50 or 55/45 | 60/40 or better |
| CGC | 55/45 or better | 60/40 or better |
| SGC | 55/45 or better | 60/40 or better |
Centering Grade Calculator
Use this reference to estimate your centering grade:
| Centering Ratio | Estimated Grade | Border Split |
|---|---|---|
| 50/50 to 55/45 | 10 (Gem Mint) | 2.25mm / 2.25mm |
| 55/45 to 60/40 | 9 (Mint) | 2.5mm / 2.0mm |
| 60/40 to 65/35 | 8 (NM-MT) | 2.6mm / 1.9mm |
| 65/35 to 70/30 | 7 (Near Mint) | 2.8mm / 1.7mm |
| 70/30 or worse | 6 or below | 3.0mm / 1.5mm+ |
Common Centering Mistakes
- Measuring in inches: Millimeters provide the precision needed. A 0.5mm difference is meaningful.
- Ignoring one axis: A card can have perfect left/right centering but poor top/bottom centering. Check both.
- Visual estimation: The human eye is poor at judging small differences. Always measure with a ruler.
- Measuring the wrong borders: Some cards have design elements that extend to the edge. Measure the printed image border, not the card edge.
Frequently Asked Questions
How do you measure card centering?
What is 55/45 centering?
What centering is needed for PSA 10?
Does centering matter for grading?
What is the best tool for measuring card centering?
Sources & Further Reading
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