Centering describes how evenly a card's borders frame the image, written as a ratio of the wider border to the narrower one, such as 60/40. 50/50 is perfect. Grading companies set centering limits for each grade; for a PSA Gem Mint 10, the front generally needs to be about 55/45 to 60/40 or better and the back about 75/25 or better. Check centering before you pay to grade a card, because it can cap the grade no matter how sharp the corners are.
Centering is often the first thing to check before grading, because it is easy to measure and can cap a card’s grade even if everything else is perfect.
How centering is expressed
Centering is written as two numbers that add up to 100, such as 55/45. Measure left versus right and top versus bottom separately, on both the front and the back.
Example: left border 3 mm, right border 2 mm. Total is 5 mm. 3 / 5 = 60%, so the card is 60/40 left to right.
Centering and grades
Each grading company publishes its own centering standards, and they differ by grade. As a general guide for PSA’s top grade, the front should be about 55/45 to 60/40 or better and the back about 75/25 or better. Lower grades allow progressively worse centering. Beckett, CGC and SGC each have their own limits, with their top Pristine grades typically requiring near-perfect centering. Always check the company’s current grading standards.
How to measure at home
- Use digital calipers or a fine ruler.
- Measure each border at the narrowest point of the printed frame.
- Calculate each axis, front and back.
- For a quick check, use a centering overlay tool or app, then confirm with measurements on valuable cards.
Tips
- Check centering before buying a raw card you plan to grade.
- Off-center cards can still be valuable, especially vintage cards where good centering is rare.
- Diamond cutting (the image slightly rotated) also affects the centering grade.
- The back matters too, though standards are looser.
The bottom line
If a card’s centering already falls outside the limit for the grade you want, factor that into whether grading is worth the fee.
Common questions
What does 60/40 centering mean?
One border takes up 60% of the combined border width on that axis and the opposite border takes 40%. The closer to 50/50, the better centered the card.
Can a well-centered card still get a low grade?
Yes. Centering is only one of four factors. Corners, edges and surface also count, and the lowest area usually limits the grade.
How do I measure centering at home?
Measure the left and right borders (and top and bottom) with a ruler or calipers, or use a centering tool or app, then divide each border by the total of both.