3 min read
Free PGN analyzer · No sign-up
Paste a chess game. See where it turned, and why.
Copy a finished game as PGN, paste it below, and pick the side you played. Stockfish 18 grades every move on your own device, then the analysis board walks you through the moments that changed the game, with a plain-English reason for each one.
The analyzer runs in your browser. Open the PGN analyzer →
Every move graded
Each of your moves is labeled from best to blunder by how much it cost, measured with Stockfish 18.
Mistakes explained
Important moves get a board-specific reason: the threat you missed, the piece left loose, or the better plan.
Stays on your device
The engine runs in your browser and the game is saved locally, with no BeaconChess account.
On this page
How to get a PGN
PGN is the plain-text format almost every chess site exports. It lists the moves and, usually, the players, ratings, and date.
On Chess.com, open a finished game, choose Share, and copy the PGN. On Lichess, open the game, go to the Share & export tab, and copy the PGN text. Any other PGN works the same way, including games typed from a scoresheet.
What the analysis shows
Once grading finishes, the game opens on the analysis board. Every one of your moves carries a grade, and an evaluation graph shows where the game swung. Step to any move to see why it earned its grade, what the stronger alternative was, and how the opponent could have punished it.
Beacon spends its words on the positions that decided the game rather than narrating every routine move, so a long game still reads as a handful of lessons.
- GradesBrilliant, great, best, good, inaccuracy, mistake, and blunder, based on how much each move changed the expected result.
- Missed chancesWhen you had a free capture, a fork, or a mate and played something else, the explanation for that move says so.
What it does not do
Automated grades and explanations can be incomplete or wrong, especially in sharp positions. Treat them as a study aid and check the lines that matter on the board.
Do not use the analyzer on a game that is still in progress. It is for reviewing finished games, not for assistance during rated play against other people.
Common questions
Clear answers before you try it.
Is the chess game analyzer really free?
The first three PGN analyses are free, with no account, email, or card. After that, a one-time personal license unlocks unlimited analyses.
Does it work with Chess.com and Lichess games?
Yes. Copy the game as PGN from either site and paste it in. Licensed users can also connect Lichess and pick a recent game without copying anything.
Is my game uploaded anywhere?
No. Stockfish runs in your browser and the analyzed game is saved in your browser's storage on this device.
Why does analysis take a little while?
Every move is evaluated on your own device rather than on a server, so long games and slower phones take longer. You can cancel at any time.
Prefer to practice instead?
Play a free coached game against a human-like opponent and get the same explanations while you play.