Chess Acuity
Offline chess analysis
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
Chess Acuity turns any chess position into insight — entirely on your device.
Set up a position and Stockfish 17, running locally on your iPhone, shows you the best moves and lines. No account, no ads, no analytics, no internet connection required. The app is free and open source.
FOUR WAYS IN
• From a photo — share a screenshot from any chess app or website, or pick one from your photo library. A built-in recognizer reads the board on-device and sets up the position.
• From a game — paste a PGN, step through the moves, and analyse any position along the way.
• By hand — set up the board in a clean, fast editor.
• By FEN — paste a position directly.
ANALYSIS
• Powered by the Stockfish 17 chess engine, running natively on your device.
• Multiple lines (MultiPV) with evaluations, searched by depth or thinking time.
• Step through any line move by move on the board.
• Plain-language explanation of the engine's choice.
PLAY
• Play a full game against Stockfish at eight strength levels.
• Take a hint when you're stuck, then hand the finished game straight to the analyser.
PRIVATE BY DESIGN
Everything — board recognition, engine analysis, move explanations — runs on your device. The app makes no network requests and collects no data. Screenshots you import are processed locally and never uploaded.
OPEN SOURCE
Chess Acuity is free software under the GNU GPLv3. The complete source code is available at github.com/alexostar/chess-acuity-app.
FAIR PLAY
Chess Acuity is made for study and review. Please don't use it for assistance during live or rated games — that breaks the fair-play rules of every chess site and spoils the game for everyone.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Chess Acuity 1.0.1 is a reliability update that makes on-device analysis feel faster and more dependable.
• Stockfish progress and results now reach the screen much faster.
• Added a Cancel button while analysis is running.
• Fixed imports containing multiple PGN games.
• Improved recovery when photo recognition, settings storage, or shared-image imports encounter a temporary problem.
• Updated open-source, licence, and privacy information.
The developer, Sigfus Bjarnason, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Sigfus Bjarnason
- Size
- 142.1 MB
- Category
- Board
- Compatibility
Requires iOS 16.4 or later.
- iPhone
Requires iOS 16.4 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Casabrava EF