CoinScanFrom photo to result
What happens when you scan a coin, and what happens to your photos along the way.
You photograph the coin
The app guides you through the front, the reverse and an optional edge photo, or you choose photos from your library. Your iPhone straightens each photo, removes its location and other metadata, and checks it for blur, glare, darkness and resolution. If a photo is unlikely to work, the app says why before anything is sent.
The photos are analysed
The photos travel over an encrypted (HTTPS) connection to CoinScan's server, which checks your daily limit and passes them to Google's Gemini vision model. The model reads the design, inscriptions, date, denomination and visible mint marks. CoinScan's server handles photos in memory and does not store them.
The catalogue is searched
CoinScan asks the Numista catalogue for the types issued by the country read on the coin in the year printed on it, then compares every result with the face value and date it read. A year the AI only guessed, or a catalogue number it suggested, is never used to search. Only these readings are sent to Numista, never your photos or personal information.
The evidence is weighed
CoinScan compares what it read with each catalogue record and counts the details that independently agree. A high confidence match needs at least two independent agreements, a photo of the reverse and no contradicting details. Fewer agreements cap the result at medium or low, and when the evidence is too weak CoinScan says it could not identify the coin.
You review the result
You see the best match with its details, the source of each one and the confidence level, plus a short explanation. The result is added to your scan history; with a free account you can also save the coin to your vault. You can create a PDF report of any result.
Tips for better results
- Use a plain, non-reflective background.
- Light the coin softly from the side to avoid glare.
- Hold the phone parallel to the coin so it looks round, not oval.
- Fill most of the frame and keep the date and inscriptions in focus.
- Always add the reverse: many coins share the same portrait.
Limits of photo identification
Wear, cleaning, corrosion, glare and counterfeits all affect what a photo shows, and identifications can be wrong. A result identifies the coin type only. CoinScan does not authenticate, grade or appraise coins.
For a coin that might be rare or valuable, use CoinScan's result as a starting point and confirm it with a specialist reference or a professional.
Try it on your own coins
You can scan without an account.