Card Centering Tool
What card centering actually means
Centering is how evenly the printed design sits between the four edges of the card. Every card is cut from a large printed sheet, and the cut is rarely dead centre, so one border ends up wider than its opposite. Graders measure the two borders on each axis and write the split as a ratio. A card with a 5 mm left border and a 5 mm right border is 50/50. A card with 6 mm on the left and 4 mm on the right is 60/40. The bigger the first number, the further off centre the card is.
You get two ratios for the front, left to right and top to bottom, and two more for the back. Graders take the worst of each side. On Pokémon cards the back is often the problem: the blue border is thin and moves around a lot from sheet to sheet, which is why every grading company gives the back more room.
What centering do you need for a 10?
Each company publishes its own limits. These are the ones that matter for the graders you'll see in our slabs.
| Grade | Front | Back |
|---|---|---|
| Ace Grading 10 (Gem Mint) | Better than 60/40 | Better than 60/40 |
| Ace Grading 9 (Mint) | Better than 65/35 | Better than 70/30 |
| Ace Grading 8 | Better than 70/30 | Better than 75/25 |
| PSA 10 (Gem Mint) | Roughly 55/45 to 60/40 | 75/25 |
| PSA 9 (Mint) | 60/40 | 90/10 |
| PSA 8 (NM-MT) | 65/35 | 90/10 |
| CGC 10 (Gem Mint) | About 55/45 | 75/25 |
Two things stand out. Ace is slightly more forgiving than PSA on the front of a 10 but far stricter on the back, where PSA lets a 75/25 back through and Ace does not. And a 60/40 back is a common sight on modern Pokémon cards, so a card that would be a PSA 10 can come back from Ace as a 9 purely on the reverse. That's not a fault in either company; they measure the same card against different rules. Beckett and CGC both keep a separate "Pristine" or black label 10 for cards that are 50/50 on the front, which is rarer than it sounds.
Ace measures every border under a microscope to a thousandth of a millimetre and uses the worst pair of opposite edges. If you want to see the number they got for your card, an Ace Grading Report shows the centering score on its own.
How to measure centering at home
You need a flat surface, good light and either a ruler marked in millimetres or a phone camera and any photo app that shows pixel coordinates. Take the card out of its sleeve; the sleeve edge throws the reading off.
- Find the right line to measure to. Measure from the card edge to the outer edge of the printed border, not to the artwork box. On a standard Pokémon card that's where the yellow border stops and the card stock begins. On a full art or Special Illustration Rare there is no yellow border, so use the outer edge of the printed design or the foil frame, whichever runs closest to the card edge. Be consistent on both sides.
- Measure all four borders on the front. Left, right, top, bottom. Write them down in millimetres, or in pixels if you're working from a photo.
- Work out each ratio. Left divided by left plus right, times 100, gives the left percentage. So 6 mm and 4 mm is 6 ÷ 10 × 100 = 60, which you'd write as 60/40. Do the same for top and bottom.
- Turn the card over and repeat. The back gets its own two ratios.
- Take the worst front ratio and the worst back ratio and read them against the table above.
If you're using a photo, shoot straight down with the card square to the frame and the whole card in shot. A few degrees of tilt changes the border widths more than you'd expect. Crop tightly to the card edge before you read the pixel positions, and check that the image hasn't been sharpened or straightened by the phone.
Mistakes that cost people a grade
- Measuring the art box instead of the outer border. The picture frame on a Pokémon card is printed independently of the border and can be off in a different direction. Graders measure the border.
- Judging by eye. A 58/42 card looks obviously off to most people and still qualifies for an Ace 10. A 61/39 looks about the same and doesn't. Measure.
- Ignoring the back. Most surprise 9s from Ace are back centering. Check it before you pay a grading fee.
- Calling a miscut "off centre". If you can see a sliver of the next card's border or the edge of the printed sheet, the card is miscut. That's a different defect and graders treat it as one.
- Measuring through a sleeve or toploader. Both distort the edge. Bare card, flat, in good light.
About the calculator
The upload and measure tool that used to live on this page is being rebuilt for the new site. Until it's back, the method above gives you the same answer with a ruler and two minutes. When you're ready to send cards off, our Ace Grading discount code takes money off the submission, and every slab we sell in the Ace graded and PSA graded collections shows its grade and certificate number on the product page.
Updated September 2026. Grading company limits change; the figures above are taken from each company's published standards at the time of writing and the source for each is on file.