Match mystery coins through precise specifications shared by collectors worldwide
Community-built reference system: Compare diameter, weight, edge type, and metal composition across twelve simultaneous candidates while learning Sheldon grading from experienced numismatists.
Activate your welcome package and join the numismatist community
All features available immediately after download. Educational content updated regularly by community contributors. No automatic grading — designed for hands-on learning.
Coin Atlas was built by collectors who understand that mystery coin identification requires systematic comparison of measurable data. The app lets you pin up to twelve potential matches simultaneously, entering precise measurements from your own calipers and scales.
Rather than relying on automated photo recognition, the community approach teaches you to observe physical characteristics — reeded versus plain edges, bronze versus zinc weight ratios, visible mint marks — the way experienced numismatists have for generations.
Daily checkpoints guide you through the Sheldon grading ladder from Poor through Mint State. Each checkpoint explains what friction patterns, rim conditions, and design visibility indicate specific grades. The app educates — it does not replace your own examination skills.
Coin Atlas emerged from the numismatic community's need for a systematic identification tool that respects the learning process. Instead of promising instant AI identification, the developers created a reference system that teaches observation skills. The app includes checkpoints based on actual bench stories — the Washington quarter clad edge feel, the bronze versus zinc weight distinctions on wheat pennies, the LIBERTY letter visibility on shield designs. Every guide was written by collectors who measure with calipers, not cameras. Updated 12.11.2026 with additional edge type references and expanded Sheldon checkpoint descriptions contributed by the user community.
Pin multiple candidates for a single mystery coin and compare specifications simultaneously. Track which possibilities remain open and which you've ruled out through systematic testing.
Keep detailed observations for each shortlist entry. Document why a candidate fails — wrong edge feel, mass outside tolerance, incorrect alloy ring — building your personal identification knowledge base.
Learn grading progression from Poor through Very Fine with detailed wear descriptions. Understand what rim visibility, portrait outline depth, and legend readability indicate at each grade level.
Reference guide covering plain, reeded, lettered-decorated, and security edge types. Learn how fingernail slide tests distinguish smooth from ridged edges and identify security features.
Test your ability to locate and identify mint marks across different coin series. Build muscle memory for D, S, P, and historical mark positions through spaced repetition.
Organize mystery coins by measured dimensions — diameter in millimeters, weight in grams, edge type, metal composition. Match your physical measurements against reference data systematically.
Free download • iOS & Android • 48 MB • Offline reference guides included
Download Coin AtlasCompatible with iOS 13.0+ and Android 8.0+. No subscription required for core features. Educational content updates require occasional internet connection. Designed for ages 12+ with interest in numismatics.