Comparison

Ding Detect vs Gemcheck

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Ding Detect

Instantly measure the centering of trading cards using your phone. Get estimated grade tiers from major grading companies and track your collection strategy. Export and share your results.

Highlights
  • Centering analysis for front and back
  • Grade predictions for major companies
  • Customizable guide controls
  • Scan history tracking
  • Dashboard performance stats
  • Export and share results
Features
Read full description

DingDetect – Card Centering Checker Know your centering before you submit. DingDetect lets you measure the centering of your trading cards in seconds and instantly see how your card stacks up against PSA, BGS, CGC, ACE, and TAG grading standards — right from your phone. Whether you're deciding which cards are worth submitting or building a collection strategy, DingDetect gives you the data you need before spending on grading fees. HOW IT WORKS Take a photo or upload from your gallery, align the guide lines to your card's borders, and DingDetect calculates the top, bottom, left, and right centering percentages. Results are mapped instantly against published grading standards so you can see your estimated grade tier for each company at a glance. FEATURES • Centering analysis for front and back of any card • Grade predictions for PSA, BGS, CGC, ACE, and TAG • Draggable guide tabs or edge sliders — choose the control style that works for you • Scan history to track and revisit every card you've checked • Dashboard stats showing total scans and per-company centering performance over time • Customizable settings — show only the grading companies you care about • Export and share your centering results as an image COMING SOON Ding Detect — AI-powered surface scanning to automatically identify dings, scratches, and print defects before you submit. FREE & PRO DingDetect is free to try with 2 scans per day. Upgrade to Pro for unlimited scans, sharing, and full access to all features. DingDetect is an independent app and is not affiliated with PSA, BGS, CGC, ACE, TAG or any other grading company. Centering estimates are based on publicly available grading standards and are for reference purposes only. Actual grades may vary.

About

Gemcheck

Features
Read full description

Gemcheck measures your card's centering the way the grading houses measure it — before you pay to find out. Photograph the front and back. Gemcheck corrects the perspective, finds the cut edge and the printed frame, and measures the border widths in millimetres. Then it tells you what PSA, BGS and CGC each allow at every grade, and where your card falls. CENTERING, MEASURED • Left/right and top/bottom, front and back • Border widths in millimetres, from a perspective-corrected image • The highest grade each house's published centering tolerance allows CORNERS, AGAINST YOUR OWN CARD Every corner is compared to the die-cut arc that card was actually made to — fitted from all four of its own corners, not assumed from a constant. You get a score out of 1000 per corner, the arc drawn over the corner itself, and a mark on the worst point, so you can see where the number came from. SURFACE, IN RELIEF A relief view lights the card from one side. Flat card falls away to an even grey and what stands up is topography: a crease, a dent, a pushed corner, the weave of the stock. Slide it over the real image at any magnification. WHAT IT SELLS FOR Gemcheck Pro identifies your exact card from its artwork and shows what copies of it are actually listed for on eBay right now — graded PSA 10, graded PSA 9, and ungraded — with photographs and asking prices. The gap between the raw price and the slab price is the whole grading decision, and it is a number, not a feeling. WHAT IS NEVER PROMISED A grade. Graders allow themselves discretion over their own published tolerances, so even a measured ceiling is a ceiling on the rule — not a guarantee. Gemcheck will not pretend otherwise. ADJUST ANYTHING The cut edge and the printed frame sit on one screen over your original photograph. Pinch to zoom, drag any line, or nudge it a hundredth of a millimetre at a time. A loupe magnifies under your finger. Nothing is measured that you cannot see and correct yourself. YOUR BINDER A saved scan keeps its photographs and its geometry, so any card can be re-adjusted or re-shot later and re-measured through exactly the same code that measured it the first time. Track what you have sent for grading, and record what came back. MEASURED ON YOUR DEVICE Every measurement happens on your iPhone and the results stay there. No account, no sign-in, no analytics, no tracking. There is one exception and we would rather lead with it than bury it: if you open the market section, one picture of the card is sent once so the card can be identified — after that it is never sent again. Measuring a card never sends anything anywhere. GEMCHECK PRO Photographing a card is free. Gemcheck measures it and saves it to your binder, and the subscription is what reveals the figures — the centering ratios, the corner scores, the surface relief, the manual adjustment tools and what the card sells for. There is no free tier and no trial: you can watch the app work on your own card, and decide from there. — Gemcheck Pro is an auto-renewing subscription. There is no free trial. • Weekly — $7.99 per week • Monthly — $14.99 per month • Yearly — $49.99 per year Prices are US dollars; your own currency is shown on the purchase screen before anything is charged. Payment is charged to your Apple ID at confirmation of purchase. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period. Manage or cancel in Settings > Apple ID > Subscriptions. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ — Gemcheck is not affiliated with, endorsed by, or sponsored by Professional Sports Authenticator (PSA), Beckett Grading Services (BGS), Certified Guaranty Company (CGC), eBay Inc., or The Pokémon Company. Grading tolerances are taken from each company's own published standards.

Screenshots

Ding Detect4 screens
Gemcheck4 screens

Verdict

The call

The clearest difference is update cadence: Gemcheck at every 2 days against Ding Detect's every 2 weeks. Ding Detect's advantage is iOS requirement (15.5 vs 26.0). On price, ads, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Ding Detect sells 1 one-off in-app purchase and Gemcheck sells 3 in-app purchases, starting at $7.99 per 7 days. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Ding Detect ships an update every 2 weeks, Gemcheck every 2 days. The most recent releases landed on October 31, 2026 and October 25, 2026 respectively.

Scorecard2 real differences · 8 level
Ding Detect versus Gemcheck: the parameters behind the verdict, then further details
ParameterDing DetectGemcheck
PriceFreeFree
Rating5.0 (2 ratings) — better—
Positive reviews100.0% of reviews—
Number of ratings2 — better—
Update frequencyEvery 2 weeksEvery 2 days — better
AdsNoNo
In-app purchasesYesYes
MonetizationFreemium—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.5 — better26.0
Further details — not scored
Size66 MB21 MB
Age rating4+4+
DeveloperTechcave, LLCChan Jing Hong

In-app purchases

1 purchases

Ding Detect

One-time1
  • Card Centering Tool$3.99
3 purchases

Gemcheck

Subscriptions3
  • Weekly$7.997 Days
  • Monthly$14.991 Month
  • Yearly$49.991 Year

Questions

Is Ding Detect free?
Ding Detect is free to download, with in-app purchases available.
Is Gemcheck free?
Gemcheck is free to download, with in-app purchases available.
Do Ding Detect or Gemcheck have ads?
Neither Ding Detect nor Gemcheck shows ads.
Which is updated more often, Ding Detect or Gemcheck?
Ding Detect ships an update every 2 weeks, and Gemcheck every 2 days. Most recently, Ding Detect was updated on October 31, 2026 and Gemcheck on October 25, 2026.

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