Pokémon TCG pre-grading · iPhone
Check your card
before you pay
to grade it.
Photograph a card and Gemcheck measures its centering to the millimetre, magnifies every corner and the surface, and shows you what your exact card is selling for on eBay — graded and raw. A minute on your phone, before you spend the submission fee.
- 63 × 88
- mm, rectified
- ±0.08
- mm, at 12 px/mm
- 0
- accounts required
Front · adjusted
63.00 × 88.00 mmAn example, drawn at true scale. The dashed lines are the printed border; the squares are the cut edge. Both are draggable in the app, and every ratio recomputes as they move.
How it works
Photograph. Correct. Read the cap.
Photograph the front and the back
The shutter stays locked until all four corners are clear of the frame and the phone is square enough that perspective can be corrected. Two shots per face, at slightly different angles — that is what makes the agreement check in step three possible.
Correct the lines yourself, with a loupe
Auto-detection is an opening bid, not a verdict. The cut edge and each of the four printed-border lines are draggable, under a magnifier that sits beside your finger rather than under it, and the ratios update as you move. Borderless full-arts have no frame to detect — so you place the reference, which is what a grader does with the same card.
See the grade each house allows, and what is holding it back
Two photographs of the same card share no error sources except the card, so Gemcheck shoots both faces and cross-checks them. You get one line per house — the highest grade its published centering rule allows — and, more usefully, which edge is costing you the points.
One card, three rulebooks
The same card is not the same grade
The measurements above, run through three different published centering tables. Collectors submit to the wrong house and lose the fee. A grade on its own is a dead end; knowing which edge is capping it, and by how much, is a decision.
10 needs 55/45 front · 75/25 reverse
The front clears 55/45. The back is 78.5/21.5, and PSA wants 75/25 for a GEM-MT 10 — 3.5 points over.
9.5 allows 60/40 front · 80/20 back
Beckett allows 80/20 on the back at 9.5, so the same back that stops PSA at 9 does not stop Beckett.
9.5 allows 60/40 front · 80/20 back
Same threshold as Beckett at this grade. CGC's Pristine 10 wants 50/50 front, which this card misses.
Tolerances are each company's own published figures, last checked on 30 July 2026 — the app shows that date, and re-checks it, because the houses change these quietly: PSA tightened its GEM-MT front tolerance in January 2025 without announcing it. Corners, edges and surface can cap any of these three far lower.
Privacy
Measuring
happens
on your phone.
Every measurement — the perspective correction, the border detection, the millimetres, the corners and surface — runs on the device, with Apple's Vision and Core Image frameworks and our own code. There is no account and no login. Your binder is stored locally, and deleting the app erases it.
One exception, stated plainly: if you subscribe and use the market, a picture of the card is sent once so it can be identified — that is what makes it possible to find listings of your exact card. It is sent once per card, never stored by us, and never sent at all if you do not subscribe.
Read the Privacy PolicyMeasured locally
Nothing is uploaded to measure a card. Free users send nothing, ever.
One picture, once
Pro identifies a card by sending one picture of it, once. We store none of it.
No account
No sign-up, no login, no profile, nothing to breach.
No analytics
No analytics, attribution or crash SDK of any kind is present in the app.
No ads, no tracking
No advertising identifier, no App Tracking Transparency prompt, no data sold.
One permission
The camera, for photographing the card being measured. That is the only one requested.
Ten palettes
The card supplies the colour
Sampling a dominant colour straight from card art gives mud — brown-grey averages, blown-out holo whites, and text that fails contrast about half the time. So the sampled colour is never used directly. It chooses from ten fixed palettes, every one of them contrast-tested, with Pokémon's own energy taxonomy as the prior and the sampled hue only breaking ties.
- EmberFire#FF6B35
- TideWater#3BA9F0
- VerdantGrass#4ED17F
- VoltLightning#F5C518
- PrismPsychic#B77BF0
- TerraFighting#E0714A
- UmbraDarkness#4A4258
- AlloyMetal#B9C6D2
- AurumDragon#8A5F1E
- BloomFairy#F26FA8
The legibility contract: chroma carries identity, never body text. A saturated fill appears once, behind type large enough to survive it. Everything else sits on near-black, where contrast is fixed and known.
Gemcheck Pro
What the card is actually selling for
Knowing the grade is half of it. The other half is whether the fee is worth paying at all. Gemcheck identifies the card from the photograph you already took — not from a collector number, which a card shares with every reprint of itself — and shows what copies of that exact card are listed for on eBay right now.
PSA 10 and PSA 9
The two grades worth chasing, each with the listings under it. Below a 9 the grading fee usually eats the difference, which is the decision this informs.
Ungraded too
What the card fetches as it stands. For a recent set with no slabs for sale, that is the only market there is — and the number the fee is measured against.
Asking, not sold
These are live listings with the seller's own photographs, labelled as asking prices. An asking price is not a sale, and Gemcheck will not round one into the other.
Pricing
One submission you don't make pays for the year
Grading a single card costs more than a year of Gemcheck Pro — and that is before the postage, the insurance and the weeks of waiting to be told what you could have known in a minute. Pro measures every card you own and prices each one against what it is actually selling for.
Free
5scans / month
- Full centering measurement, front and back
- Full manual adjustment, with the loupe
- PSA, BGS and CGC, and which edge is costing you
- Your binder, stored on device
Gemcheck Pro · yearly
1 week free$39.99/ year
- Unlimited scans
- Live eBay listings for your exact card
- PSA 10, PSA 9 and ungraded, priced and pictured
- One week free, then billed yearly
- Cancel any time in iOS Settings
Gemcheck Pro · monthly
$5.99/ month
- Unlimited scans
- Live eBay listings for your exact card
- No free trial on this plan
- Cancel any time in iOS Settings
Prices in US dollars; other storefronts follow Apple's price tiers and local tax may apply. Subscriptions renew automatically unless cancelled at least 24 hours before the period ends, and are managed and cancelled through Apple, not through us. Purchasing is not enabled yet — the app is not on the App Store. Full terms are in the Terms of Use.
Measure the card before you pay to grade it.
Know what you are sending, and what it is worth, before the fee leaves your account.
Coming to the App Store