Measure card centering. Know which cards are worth grading.

SlabbyPrep measures a trading card’s centering from a photo, checks it against the centering lines PSA, BGS, CGC, SGC, TAG and ACE publish, and works out whether grading pays after each company’s fee, with the card’s prices looked up for Pokémon, Magic, Yu-Gi-Oh!, One Piece, Lorcana and more (sports prices you enter). Both axes are reported to 0.01 mm; on synthetic test photos, 97% of the readings shown without a warning were within 1 percentage point (how we measure). Runs in your browser; photos never leave your device. From CrabTree Collections, a trading-card store in Tamarac, Florida.

1. Shoot the card. Straight on, whole card in frame; the outline is found automatically.
2. Measure and rank. Both axes, front and back, against each of the six graders’ published lines.
3. Decide with numbers. Expected value after each service’s fee and tier, or keep it raw.

$3/month, cancel anytime. No account. US only for now. Estimates from published standards and fees, not a guarantee of any grade or price. 18+.