Chessigma
Analyze Games

Free Chess Analysis Board

Paste a FEN or PGN, explore variations, and read Stockfish 17's evaluation in real time. Runs in your browser, no sign-up.

How the Chess Analysis Board Works

This online chess analysis board uses Stockfish 17, the world's strongest open-source chess engine, to evaluate any position you set up. Everything runs locally in your browser through WebAssembly — no positions are sent to a server, and there is no rate limit.

Load a game by pasting a PGN, jump to a single position with a FEN string, or just play moves from the starting position. As you click through the move tree, the engine continuously updates its evaluation, principal variation, and depth. Try alternative moves and the board branches into a side line you can explore independently.

The current position is mirrored back into the URL as a ?fen= parameter — this chess analysis board carries the FEN in the URL automatically, so you can copy the link to share or bookmark the exact position you are looking at.

Three Ways to Load a Position

Paste a PGN

Drop in any PGN — from Chess.com, Lichess, or a tournament report — and step through every move with engine evaluation.

Paste a FEN

Jump straight to a specific position from a book, puzzle, or live game. The engine starts analyzing the moment the FEN is valid.

Play From Scratch

Start from the opening position and play moves on the board to reach the position you want to analyze.

Need to set the position from scratch with arbitrary pieces? Use the chess board editor.

Reading the Engine Evaluation

+1.0White is ahead by roughly one pawn
-2.5Black is ahead by roughly 2.5 pawns
#3Forced checkmate in 3 moves
0.0The position is roughly equal

Evaluations are always from White's perspective. Deeper search produces more accurate numbers.

Free Alternative to the Chess.com Analysis Board

Most chess sites limit how much you can analyze for free. The Chess.com analysis board caps free Game Review at one game per day and locks deeper engine lines behind a paid plan. Lichess offers an unlimited free analysis board — Chessigma matches that and adds a focused move-review interface, a 9-tier move quality grading system, and a built-in position editor.

Chessigma runs Stockfish 17 directly on your device. There is no daily quota, no premium tier required for the engine, and no account creation. Need to review a full game with annotations and reports? Run a full game review on the home page.

Frequently Asked Questions

What is a chess analysis board?

A chess analysis board is an interactive board paired with a chess engine. You set up any position, play moves, and the engine instantly evaluates each one. Chessigma's analysis board uses Stockfish 17 running in your browser, so analysis is unlimited and free.

How do I use this analysis board?

Paste a PGN to load a full game, paste a FEN to jump to a specific position, or simply play moves on the starting position. The engine evaluation, best lines, and depth update in real time as you explore.

Is this analysis board really free and unlimited?

Yes. Stockfish runs entirely in your browser via WebAssembly, so there are no server costs to pass on. No sign-up, no daily limits, no premium tier required.

Is this a free alternative to the Chess.com analysis board?

Yes. The Chess.com analysis board limits free users to one Game Review per day and gates deeper engine analysis behind a premium subscription. Chessigma's chess analysis board has no such limits — explore unlimited positions at full Stockfish 17 strength without paying.

How is this different from the Lichess analysis board?

Both are free and run Stockfish in the browser. Chessigma adds a 9-tier move quality grading system, opening database integration, and a one-click handoff to a position editor. Lichess has a larger opening explorer; Chessigma has a more focused review-style UI.

Does this chess analysis board put the FEN in the URL?

Yes. As you move through the position the URL updates with a ?fen= parameter automatically. Copy the URL to share or bookmark the exact position — anyone who opens the link sees the same board you do, no account or upload required.

Can I save or share a position?

Yes. The current FEN is mirrored to the URL automatically — copy the URL and you are sharing the exact position you are viewing. You can also paste a FEN to load a position from another tool or book.

How deep does Stockfish analyze?

Stockfish 17 reaches depth 20+ on most modern devices, often higher with multi-threaded WebAssembly. Mobile devices reach lower depths but still play well above any human level.

Need to set up a position from scratch? Open the chess board editor

Just want one best move? Try the move calculator

Review a Full Game for Free