How accurate is Stockfish compared to human players and other engines?

Stockfish is much stronger than human players in tactical calculation, but engine output still needs interpretation. Short browser analysis is useful for finding blunders, missed tactics, and candidate moves; deeper or repeated analysis can be helpful in complex positions where the first line may not explain the whole practical lesson.

Is ChessAnalysis Pro really free? What's the catch?

Yes, the chess analysis tool is free to use with no account, trial, subscription, or credit card required. The site may use privacy-respecting analytics and, after AdSense approval, may display advertising to support hosting and maintenance.

Do I need to install software or create an account?

No installation or account required. Chess Analysis runs entirely in your web browser using technology. Simply visit the website from any modern browser (Chrome 87+, Firefox 89+, Safari 15+, Edge 88+) and start analyzing immediately. Works on Windows, macOS, Linux, iOS, and Android. Your analysis starts in under 2 seconds with no downloads, no sign-ups, and no configuration needed.

Is my chess game data private and secure?

Your chess game data is processed locally in your browser by the client-side Stockfish engine. We do not require accounts and do not upload your PGN for engine analysis. The site may still use analytics or advertising cookies for page-level measurement, as described in the Privacy Policy.

What chess formats and platforms are compatible?

Chess Analysis supports standard PGN (Portable Game Notation), the common export format used by major chess platforms and database tools. You can also enter a FEN position for single-position review. If a PGN contains unusual annotations or malformed move text, clean the notation first so the move list can be parsed correctly.

How can I use this tool to improve my chess rating?

Use analysis as a review habit rather than a shortcut. A practical workflow is: (1) Review recent losses to identify patterns; (2) Focus on positions where the evaluation changed sharply; (3) Study the engine's suggested alternatives and explain why they work; (4) Track recurring error types such as tactical misses, time-pressure decisions, weak endgame technique, or poor opening choices.

What analysis depth should I use and how long does it take?

Start with a moderate depth for a fast review, then increase depth on critical positions where the evaluation changes sharply or the suggested line is not obvious. Runtime depends on your device, browser, and position complexity, so mobile devices and older laptops may benefit from lower depth settings.

Can I analyze games on mobile devices?

Yes, fully optimized for mobile. Chess Analysis works on iOS (iPhone/iPad with Safari 15+) and Android (Chrome 87+) with a responsive touch-friendly interface. Mobile analysis runs slightly slower than desktop (typically 30-50% slower due to CPU limitations) but remains highly usable. For best mobile experience: use WiFi for page load, close background apps for maximum performance, and consider depth 12-15 for faster analysis. Full feature parity with desktop version.

Does this work for chess variants like Chess960 or 3-check?

Currently, Chess Analysis supports standard chess only (FIDE rules). We use the standard Stockfish build optimized for classical chess. Chess variants (Chess960/Fischer Random, Three-Check, King of the Hill, Crazyhouse, etc.) require specialized engine builds and are not yet supported. Planned for future releases based on user demand. For now, please use Lichess for variant analysis as they have native support for multiple variants with specialized engines.

Can I share my analyzed games with others?

Yes, use the Share feature to create a link for discussing a game with another player, coach, or study group. Review shared content before sending it, especially if the game is private preparation or from an ongoing event.

Free Online Chess Game Analysis

Stockfish Engine Powered • 100% Free & Private • Instant Browser Analysis

Game Input

Step 1

Choose your game source

Upload PGN File or Paste PGN

Game Board

Step 2

Game Analysis

Step 3

Load a game and click "Analyze" to see move-by-move evaluation

Featured Chess Game Analysis

Discover how Chess Analysis uncovers hidden insights from real chess games

Sample middlegame position

Tactical Turning Point

+3.5

-2.1

Compare the evaluation before and after a candidate move to see whether a tactical resource changes the character of the position.

Evaluation swing
Candidate moves
Tactical review

Sicilian Defense - Najdorf Variation

Opening Choice Review

+0.3

+1.8

Use engine feedback to check whether an early move supports development, king safety, and a playable middlegame plan.

Opening structure
Plan comparison
Follow-up ideas

Sample rook endgame

Endgame Precision Study

0.0

+0.9

Small endgame decisions often change practical chances. Review the engine line, then translate it into a human plan.

Rook activity
King position
Conversion plan

How Chess Analysis Works

Three simple steps to transform your chess understanding

Import Your Chess Game

Paste your game in standard PGN notation format or load one of our sample games. Our system supports games from any chess platform including Chess.com, Lichess, and FEN strings.

Engine Analyzes Moves

Stockfish engine evaluates every position at depth 15+ using advanced algorithms. It runs directly in your browser for maximum speed and privacy.

Review Insights & Improve

Navigate through your game move-by-move with detailed evaluations, best move suggestions, and strategic commentary. Identify blunders, tactical opportunities, and positional advantages.

Features of Chess Analysis

Our free chess analyzer combines Stockfish engine technology with a focused review workflow. Analyze games online, study tactical patterns, and turn mistakes into practical training notes.

Stockfish Engine Powered

Use Stockfish engine analysis to review candidate moves, tactical swings, and position evaluations directly in your browser.

Lightning-Fast Analysis

Experience real-time position evaluation with millions of nodes per second. Get instant tactical insights and strategic recommendations without delays.

Local PGN Analysis

Your PGN is analyzed locally by the browser engine. The site does not require an account or upload your game for engine processing.

Universal Browser Access

No downloads or installations required. Analyze games from any device with a modern web browser—desktop, tablet, or mobile.

Move-by-Move Breakdown

Navigate through every position in your game with detailed evaluations. Identify turning points, tactical mistakes, and missed opportunities with precision.

Improvement Insights

Understand evaluation swings and critical moments. Learn from mistakes with alternative move suggestions and strategic explanations.

Practical Study Workflows

Use engine analysis as a structured review process: find the turning point, understand the better move, and turn that lesson into the next training task.

Post-game review

Paste a PGN after a game, scan the evaluation changes, and mark the positions where your plan or calculation went wrong.

Training notes

Turn recurring mistakes into a short study list: missed tactics, poor exchanges, weak king safety, endgame technique, or time-pressure habits.

Coach discussion

Use engine lines as a starting point for explanation, then compare candidate moves and human plans instead of memorizing a single top move.

Private analysis

Run the Stockfish engine in your browser for local analysis of your PGN, useful when you do not want game preparation uploaded for engine processing.

Chess Analysis FAQs

Answers to common questions about using Stockfish engine analysis to review and improve your chess games

Chess Analysis is a free, browser-based chess game analyzer powered by Stockfish. Paste a PGN, choose an analysis depth, and review the engine evaluation, best move suggestions, and marked mistakes move by move. The engine runs locally in your browser, so your PGN does not need to be uploaded for analysis.

Ready to Elevate Your Chess Game?

Join thousands of chess enthusiasts using Chess Analysis to analyze games, discover tactical improvements, and master strategic concepts. Start your journey to stronger chess today — completely free!

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