A chess scanner that shows its work
ScanChess turns photos of handwritten scoresheets into rule-checked, editable PGN, and board images into positions you can analyze. Here is how it reads a sheet, how accurate it is, and what happens to your photos.
The basics
- Made by
- SudoAI, a small software studio
- Payments
- Waffo, the merchant of record for web purchases
- Free tools
- 23, all in your browser
- Support
- support@scanchess.com
How recognition works
Four steps from a photo to a game you can trust: the model reads, the rules check, and you decide.
Your photo
A photo of the scoresheet, or several pages of one game, taken flat and in even light.
The model reads
A vision model reads the handwriting on each photo and proposes a move for every cell, with a confidence score.
The rules check
The proposed moves are replayed on a board with chess.js. A move that is illegal in its position, or that the model was unsure about, is flagged. Nothing is corrected silently.
You confirm
You check the flagged moves against your scoresheet in the editor — retype a move, pick one of the alternatives the rules allow, insert or delete a move — then export the PGN or save the game.
Recognition quality depends on the handwriting, the lighting and the notation. Rather than quote one accuracy figure, we publish our test move by move. Expect to check a few moves in a typical game.
How accurate is it? We publish the test.
We test the reader on sample scoresheets and publish the results, sheet by sheet.
See the accuracy test- 141 of 143 moves read right first time on 3 standard algebraic scoresheets
- 141/143
- 43 of 45 moves on a clean real German scoresheet
- 43/45
- Blank scoresheets don't get invented moves
A small test, not a guarantee: always compare the moves with your sheet.
Your photos and your data
- Board screenshots in the best move finder are read in your browser and never uploaded; so are screenshots in the extension from version 1.6.0.
- A scoresheet photo is kept with its game in your account until you delete it. Deleting a game removes its photos; deleting your account removes everything.
- Card details go to Waffo, the merchant of record. ScanChess never sees them.
- Most free tools run entirely in your browser; a tool that sends something says so on its page.
What it does not do
- It does not guarantee an error-free transcription. A flagged move is one to check; an unflagged move can still be wrong when a misread was confident.
- It reads algebraic notation (e4, Nf3, O-O), including long algebraic (e2-e4), a P prefix for pawns, piece letters in several languages and figurines. Descriptive notation (P-K4) is not converted.
- It does not upload games to Lichess or Chess.com for you. It gives you a standard .pgn file, which those sites and desktop programs import.
- Scanning uses credits and needs an account. The 23 free tools work without signing in; their optional extras — AI explanations and reading a photo of a real board in the best move finder — need a free account with a verified email.
Why it exists
Over-the-board games end up as a stack of paper, and typing them into a database is slow enough that most are never looked at again. We wanted the step from a scoresheet photo to a game you can replay to take about a minute — including the checking.
Elsewhere on this site
- Scan accuracy — every move from our public scoresheet test, misreads included
- Free chess tools — all 23 of them, in your browser
- Security — how uploads and accounts are protected, and how to report a vulnerability
- Status — a live check of the website and the scanning API
- Changelog — what shipped and when
- Contact — email the team about a bad scan or a billing question
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