Chess Blunder Trainer — Learn from Your Own Blunders
Stop repeating the same blunders. This free chess blunder trainer takes the mistakes from your own chess.com and lichess games and replays them as puzzles, so you drill the exact positions where you went wrong instead of solving random tactics.
Just enter your chess.com or lichess username and it pulls your recent games automatically, finds the moves that cost you material or the game, and turns each one into a puzzle. Everything runs in your browser with no signup and no daily limit.
Training on your own blunders works because the positions come from your real games, your openings and your thinking patterns — the mistakes actually costing you rating right now. You saw the position, you missed the move, and now it comes back until you catch it every time.
Why a blunder trainer beats random puzzles
Trains your real mistakes
Every puzzle is a position from your own game where you blundered, so you fix the exact patterns costing you rating instead of a generic curriculum.
Finds the move you missed
Stockfish analyzes each game, flags the moves that lost material or the game, and shows you the stronger move you should have played.
chess.com & lichess games
Enter your chess.com or lichess username and your recent games load automatically — no PGN files, nothing to install, and no account to link.
Choose the severity
Drill only serious blunders, or widen the net to include mistakes and inaccuracies for more frequent, gentler practice.
Repeat until it sticks
The positions you keep missing come back, so a blind spot actually closes instead of resurfacing in your next game.
Free and private
The engine that builds and checks the puzzles runs locally on your device, so your games are never uploaded — no account and no daily limit.
How to train on your blunders
Enter your username
Type your chess.com or lichess username and your recent games load automatically, ready to be mined for mistakes.
Pick the severity
Choose whether to train on full blunders only or to include mistakes and inaccuracies as well, depending on how hard you want to work.
Find the move you missed
You get the exact position from your game and must find the better move — Stockfish checks your answer against its best line.
Build the habit
See why your original move failed, then move to the next blunder and keep going until spotting the pattern becomes automatic.
Frequently asked questions
What is a chess blunder trainer?
It is a tool that takes the blunders and mistakes from your own games and turns them into puzzles, so you train on your real weaknesses instead of random tactics. You replay the position where you went wrong and find the move you missed.
How does it find my blunders?
Enter your chess.com or lichess username and Stockfish analyzes your recent games in your browser, flagging the moves that lost material or the game and turning each into a puzzle.
Why train on my own blunders instead of normal puzzles?
Random puzzles announce that a tactic is present; real games do not. Training on your own blunders drills the exact patterns costing you rating, in your own openings, so the practice transfers directly to your games.
Is it free?
Yes, completely, with no signup and no daily limit. Everything runs locally in your browser, so there is no cost and your games are never uploaded.
Can I choose how hard the puzzles are?
Yes. You can train on serious blunders only, or widen the selection to include mistakes and inaccuracies for more frequent, easier practice.
Do you upload my games to a server?
No. Your games are fetched from chess.com or lichess and analyzed entirely in your browser with Stockfish, so nothing is stored on our servers.