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

Stockfish is the world's top-rated chess engine with an estimated Elo of 3600+, approximately 1000+ rating points above the strongest human grandmasters (rated ~2800). At depth 15+, Stockfish accurately identifies 99%+ of tactical combinations and evaluates positions with precision equivalent to months of human analysis. Our implementation matches the accuracy of premium platforms like Chess.com Diamond membership and Lichess Cloud Analysis, but runs entirely free in your browser.

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

Yes, 100% free with no hidden costs, trials, or premium upgrades. There's no catch—we built this as an open-source project to democratize access to professional chess analysis tools. Unlike Chess.com (requires Diamond at $14.99/month for unlimited analysis) or ChessBase (€179.90 one-time), we provide unlimited game analysis, full Stockfish engine access, and all features at zero cost. No ads, no account required, no credit card ever.

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?

Absolutely. Your privacy is guaranteed by our architecture. All game analysis happens 100% locally in your browser using client-side JavaScript and your PGN data NEVER gets uploaded to any server. We don't store, log, track, or have any access to your games. No cookies, no analytics tracking your chess data, no cloud storage. This makes ChessAnalysis Pro ideal for serious players protecting preparation secrets, coaches reviewing student games, and anyone valuing confidential analysis.

What chess formats and platforms are compatible?

Chess Analysis supports standard PGN (Portable Game Notation), the universal format used by all major chess platforms. Compatible sources include: Chess.com (export from game archive), Lichess.org (download game PGN), ICC, FICS, Chess24, FIDE tournament games, ChessBase, Fritz, Arena, and any platform offering PGN export. We support games with annotations, variations, clock times, and NAGs (Numeric Annotation Glyphs). FEN import for single position analysis coming soon.

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

Regular game analysis is proven to improve chess ratings. Our recommended workflow: (1) Review your recent losses to identify patterns in mistakes—Stockfish flags blunders (evaluation drops >200cp), mistakes (>100cp), and inaccuracies (>50cp); (2) Focus on critical positions where evaluation swung dramatically; (3) Study the engine's suggested alternatives and understand WHY they're better; (4) Track recurring error types (tactical blindness, time pressure mistakes, weak endgame play). Studies show players who analyze games weekly improve 100-200 rating points per year versus 50-100 for those who don't.

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

Default depth 15 is optimal for most players (balances accuracy and speed, completes in 0.5-3 seconds per position). Recommendations by rating: Beginners (0-1500): depth 12-15 sufficient for finding major errors; Intermediate (1500-2000): depth 15-18 for tactical accuracy; Advanced (2000+): depth 20+ for positional nuances and deep preparation. Depth 18 takes ~3-8 seconds per move on average hardware. Higher depths improve accuracy marginally: depth 15 vs 20 differs by ~20 Elo in playing strength.

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 generate a unique URL containing your game and analysis results. Shared links are view-only, permanent, and work without accounts. Recipients can review the game move-by-move with all evaluation data, export to PGN, or re-analyze at different depths. Perfect for coaches sharing annotated games with students, content creators embedding analysis in articles, or tournament players discussing games with peers. Shared data is stored efficiently and remains accessible indefinitely.

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

Kasparov vs. Deep Blue, 1997

Tactical Brilliancy Detection

+3.5

-2.1

Identified critical tactical oversight in move 24, revealing a forced combination that shifted game control.

Deep analysis
23 moves analyzed
12 improvements found

Sicilian Defense - Najdorf Variation

Opening Preparation Analysis

+0.3

+1.8

Discovered optimal deviation from theoretical lines, providing significant advantage in complex middlegame positions.

15-move sequence
3 novelties
+1.5 improvement

Carlsen vs. Caruana, 2018

Endgame Precision Study

0.0

+0.9

Revealed subtle endgame technique that converted equality into winning advantage through precise maneuvering.

40+ move sequence
Rook endgame
Conversion shown

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 intuitive design. Analyze chess games online, study tactical patterns, and improve your chess rating with professional-grade game analysis tools.

Stockfish Engine Powered

Leverage Stockfish, the world's strongest open-source chess engine with 3500+ Elo rating. Get GM-level chess position analysis, tactical evaluation, and move recommendations for free.

Lightning-Fast Analysis

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

Complete Privacy Protection

Your games never leave your browser. All analysis runs locally, ensuring absolute privacy and data security for your chess studies.

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.

What Chess Players Say

Join thousands of chess players who use our free Stockfish-powered analyzer to improve their game. From beginners to tournament players, see how our tool helps players at every level.

"This tool helped me identify recurring tactical mistakes in my games. After analyzing 20+ games, my rating jumped 150 points in 3 months. The Stockfish engine catches things I would never see on my own."

"I use this with all my students. The move-by-move breakdown is perfect for teaching. It's completely free, runs fast, and most importantly - the privacy aspect means students can analyze their games without concerns."

"Having Stockfish analysis right in my browser is a game-changer. No subscriptions, no uploads, instant results. I analyze my tournament games immediately after playing. The evaluation charts help me understand where I went wrong."

5.0 Average Rating

2,500+ Games Analyzed Daily

100% Free & Private

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 16—the world's strongest open-source chess engine (rated 3600+ Elo). Simply paste your game in PGN format, and the engine evaluates every position at depth 15-20 with multi-pv analysis, providing centipawn evaluation, best move suggestions, tactical alerts for blunders and mistakes, and opening classification. All processing happens locally using technology, ensuring your games remain private while delivering analysis speeds of 1-3 million nodes per second on modern hardware.

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!

No sign-up required
100% free forever
Private & secure