Stockfish 18 Chess Engine
The world's strongest chess engine — 3500+ ELO — running free in your browser. No download, no installation. Analyze any position instantly.
Free — runs in your browser
About Stockfish 18
Stockfish is a free, open-source chess engine that has dominated computer chess since 2008. With a rating over 3500 ELO on the CCRL list, it is dramatically stronger than any human player — over 600 points above Magnus Carlsen's peak rating of 2882.
Stockfish 18, released January 2026, uses NNUE (Efficiently Updatable Neural Network) evaluation combined with alpha-beta pruning search. NNUE is a lightweight neural network that evaluates positions with near-perfect accuracy while remaining fast enough to search millions of positions per second.
Chess Calculator runs Stockfish 18 via WebAssembly — the engine executes directly in your browser with zero server dependency. This means instant analysis, complete privacy (your positions never leave your device), and no download required.
Stockfish vs Other Chess Engines
Stockfish has consistently ranked #1 in computer chess for over a decade. Here's how it compares:
Stockfish is open-source and free. Most commercial chess software uses Stockfish as their analysis engine.
How Stockfish Runs in Your Browser
Chess Calculator uses WebAssembly (WASM) to run Stockfish 18 natively in your browser. WebAssembly compiles the Stockfish C++ code into a format that runs at near-native speed in Chrome, Firefox, Safari, and Edge.
This means: no server round-trips (instant analysis), complete privacy (positions stay on your device), and cross-platform compatibility (works on any device with a modern browser). The trade-off is that browser-based analysis is slower than the desktop app — about 5-10 seconds per position vs under 1 second on desktop.
Frequently Asked Questions
What is Stockfish?
Stockfish is the world's strongest open-source chess engine, rated over 3500 ELO on the CCRL rating list. It's free, open-source, and used by grandmasters worldwide for game preparation and analysis.
What version of Stockfish is this?
Chess Calculator uses Stockfish 18, released in January 2026. It features improved NNUE neural network evaluation and enhanced search algorithms.
How does Stockfish run in the browser?
Stockfish 18 runs directly in your browser via WebAssembly (WASM) technology. No installation, no server calls — the engine runs entirely on your device for instant analysis.
Is Stockfish stronger than Magnus Carlsen?
Yes, significantly. Stockfish is rated over 3500 ELO while Magnus Carlsen's peak rating was 2882 — a difference of over 600 points. Stockfish would be expected to win the vast majority of games against any human player.