Gemly

Trading Card Centering Measurement Tool

Before sending your cards to a grading company,check how good your card's centering is yourself.

Key Features

From shooting a card to checking the centering score — simple and precise

Automatic Capture Correction

Photograph a card and it is automatically straightened.

Easy Border Alignment

The outer card edge is aligned automatically — you only need to fit the inner artwork border to be ready.

Precise Adjustment

Zoom in on a measurement grid to fine-tune the position with precision.

Instant Results

Instantly view the top/bottom and left/right border ratios (e.g., 52/48) and the centering score.

Save Your Measurements

Save your results and review them again anytime.

How to Use

Four steps are all it takes

1

Photograph the Card

Photograph the card you want to measure and it is automatically straightened.

2

Fit the Border

The outer card edge aligns automatically. Just fit the inner artwork border.

3

Fine-Tune

Zoom in on the grid to adjust the position precisely.

4

Review & Save

Check the top/bottom and left/right border ratios and the centering score, then save the result.

Frequently Asked Questions

Have a question? Take a look here first.

Is the measurement an official grading result?
No. Gemly is a reference measurement tool, and its results are not official grading results. Use it to estimate your card’s centering before submitting to a grading company. Actual grading results may differ depending on each grading company’s standards and review.
Which cards can I use it with?
It works with common trading cards that have a border, such as Pokémon cards, sports cards, and TCG cards. The clearer the artwork border, the more accurate the measurement.
How is the centering score calculated?
It compares the top/bottom and left/right margins between the card edge and the inner artwork border to calculate a ratio (e.g., 52/48), and derives a centering score from it. The closer to 50/50, the better the centering.
My photo is tilted — do I need to retake it?
Slight tilt is corrected automatically by the straightening feature. However, if the card is heavily tilted, out of focus, or has strong glare, retaking the photo will help you get a more accurate result.
Where can I view my saved measurements again?
Results you save after measuring can be reviewed anytime in the in-app history list.
Measurement is not working or an error occurs.
Please update the app to the latest version and try again. If the problem persists, email us via Contact below with your device model, OS version, and a description of the issue, and we will help you promptly.

Contact

If you run into a problem while using the app or have an idea for improvement,email us anytime. We reply within 1–2 business days.

admin@onnomads.com

Including your device model, OS version, and a description of the issue helps us assist you faster.

This app is a reference measurement tool, and its results are not official grading results. Actual grading results may differ depending on each grading company's standards and review.

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