Shoot straight down, card flat
Perspective is measurement's first enemy: a few degrees of angle artificially widens one margin. Lay the card flat and keep the lens parallel to it, not tilted towards it.
Measure centering, on your photo.
Drop a photo, align the rulers on the card edges and on the printed frame: the left/right and top/bottom ratios compute live, and the verdict lands for each grading company. The photo never leaves your browser.
In short
To measure a card's centering, compare the widths of opposite margins: the left/right ratio is the wider margin over the sum of both horizontal margins, and the top/bottom ratio works the same way. Grading companies judge the worse of the two axes. PSA requires 55/45 or better on the front for a 10 and 60/40 for a 9 (a ladder tightened in early 2025); BGS asks 50/50 for a centering 10 and 55/45 for a 9.5; CGC grants the 10 up to 55/45. This tool takes the measurement on your photo, locally, and translates it into the highest compatible grade at each company.
Tool — centering measurement
Drop your card photo
Card flat, shot straight down, all four edges visible. You will then align the green rulers on the card edges and the gold ones on the printed frame.
The photo stays in your browser: nothing is uploaded, nothing is stored.
The published thresholds, company by company
Share of the dominant side on the worse axis — the “55/45” convention means the wider margin takes 55% of the total.
| Company | Grade | Front max | Back max |
|---|---|---|---|
| PSA | 10 — Gem Mint | 55/45 | 75/25 |
| PSA | 9 — Mint | 60/40 | 90/10 |
| PSA | 8 — NM-MT | 65/35 | 90/10 |
| BGS | 10 — centering | 50/50 | 55/45 |
| BGS | 9.5 — centering | 55/45 | 60/40 |
| BGS | 9 — centering | 60/40 | 70/30 |
| CGC | 10 | 55/45 | 75/25 |
| CGC | 9.5 | 60/40 | not published |
| CGC | 9 | 65/35 | not published |
Thresholds verified on 5 August 2026 — the PSA ladder was tightened in early 2025. Official grids prevail; below the published thresholds the tool invents no number.
Four habits for a reliable measurement
Diffuse light, no hard glare
A shadow cast along one edge visually shifts the card's boundary. Indirect daylight or a well-lit room is enough — avoid direct flash.
Frame tight, but keep all four edges
The more pixels the card occupies, the finer the ruler adjustment. All four edges must stay visible, with no finger covering one.
Fine-tune with the keyboard
Select a ruler and use the arrow keys: 0.2% per press, 1% with Shift. On a well-shot card, that is the difference between “about 60/40” and a usable measurement.
Frequently asked questions — measuring centering
How accurate is the measurement?
As accurate as your photo. On a straight-down shot with the card flat, the percentage measurement is reliable, because a ratio of margins does not depend on resolution. A tilted photo skews the margins — the first thing to check if a result surprises you.
Why judge the worse of the two axes?
Because that is what graders do: a card perfectly centered left-to-right but shifted upwards is off-center, full stop. The verdict shown by the tool therefore uses the less favourable of the left/right and top/bottom ratios.
Where do the displayed thresholds come from?
From the ladders the companies themselves publish, verified on 5 August 2026 — the PSA ladder having been tightened in early 2025. Where a company publishes no threshold (CGC's back below the 10, for instance), the tool says so rather than inventing a number. Official grids prevail.
Are my photos uploaded anywhere?
No. The measurement is done by your browser: the image is read locally, nothing is sent, nothing is stored. The daily measurement counter is purely local too — nothing leaves your device.
How many free measurements per day?
Three, without an account — the same rhythm as the free tier's full analysis. The limit resets every day, and the sample card does not consume it. Since centering is the criterion that decides the most grades, the tool is meant for checking your cards of the day, not sorting a whole box: beyond that, that is the full analysis's job.
What about the other three criteria?
Centering is the only criterion you can measure with a ruler on a photo — which is why this tool exists. Corners, edges and surface require a finer read of the image: that is what the full GradeMate analysis does, on both faces, with a detailed report.
Read next
Centering is one criterion out of four
Corners, edges and surface make up the rest of the grade. The full analysis measures them on both faces, in about thirty seconds.