Free tool
Chess opening analyzer
An opening explorer tells you how the world scores in a line. This tells you how you score in it. Audit Chess ranks every opening you play by your own win/draw/loss, worst first, so the lines that quietly lose you rating stop hiding behind an okay overall record - then shows you what to fix in each one. Free, in your browser, no account.
Your results, not the database’s
Most opening tools rank moves by how a huge database of strangers performs. Useful for learning theory, useless for finding your leaks - because a line can be perfectly sound and still be your worst opening, simply because you never learned the middlegames it leads to. The opening tree is built from your games only, so every branch shows your real score and you can walk forward to the exact move where it collapses.
That collapse point is the highest-value thing to study: it is almost always the first position you reach without a plan. Fix that one move and the whole line starts scoring.
From “this opening loses” to a fix
Once the analyzer flags a weak opening, the rest of Audit Chess helps you do something about it: the blunders you make in that line become puzzles from your own games, and the weakness view ties the opening to the mistakes it produces. For the study method, read chess opening preparation and how to improve your opening.
Analyze your openings, or an opponent’s
The same tree works as a scouting tool. Point it at an opponent and you see the openings where they score worst, matched to your repertoire so you play lines you already know. Or widen out to a full game analysis to see how your openings connect to the rest of your play.
Curious where openings go wrong for everyone, not just you? Explore our opening trap tree - a database of common opening traps mined from master-level games - to see the tricks that catch players in the lines you play.
What a weak opening looks like
Say you play the London System. Overall you score a respectable 52%, so nothing on your profile suggests a problem. But drill into the tree and the picture changes: down the line where Black replies with an early …Bf5, you are at 31% over 40 games - and your score falls off a cliff the moment you play an automatic Bd3 and trade off your good bishop.
That is the whole point of the analyzer. The opening is not “bad” - one specific move in one specific line is bad for you, and it was hidden inside a healthy-looking average. You would never find it in an opening database, because the database does not know which middlegames you understand. Fix that one move and the 31% line starts climbing toward your real level.
Transpositions, sidelines and move order
Openings are messy in real games: the same middlegame structure arrives through different move orders, sidelines transpose into main lines, and a single ECO code can hide several plans. The tree groups your games by the positions you actually reached and by ECO opening, so a line you reach three different ways is read as one opening rather than scattered across unrelated branches - which is what makes the win/draw/loss numbers at each node trustworthy.
It also means the analyzer catches the branches theory books skip: the quiet sideline your opponents keep choosing, the move order that dodges your prep, the transposition that lands you in a structure you have never studied. Those off-book positions are where club games are decided, and they are exactly where your own results shine a light that opening theory can not.
Who is it for?
Repertoire builders
You have chosen your openings but do not know which lines are actually working. See every branch of your repertoire ranked by your own score, so you sharpen what wins and drop what quietly loses.
“I never know what to do after the opening”
The tree pinpoints the exact move where your results collapse - almost always the first position you reach without a plan. That single move is what to study, instead of memorising more theory you will not remember.
Players prepping an opponent
Point it at any Chess.com or Lichess username and steer toward the openings where they score worst, matched to lines you already play well.
Coaches
Load a student’s username and see their whole repertoire ranked by result in one screen, so the opening lesson writes itself.
What is Audit Chess?
Audit Chess is a free chess analysis platform for your Chess.com and Lichess games. It does two jobs in one place. First, it reviews any single game move by move with Stockfish: every move graded from Brilliant to Blunder, accuracy by game phase, an eval graph, and a plain-English, engine-checked explanation of each key moment. Second, it analyzes your whole history at once to find what a single game can't show: the openings that cost you points, your mistakes ranked by tactical, positional and endgame theme, the wins you throw away, missed mates, and your endgame and playstyle profile. Then it turns your own blunders into Stockfish-verified puzzles and drills. It runs in your browser, needs no account, has no review limit and never uploads your games.
In short: a complete free alternative to a paid per-game review, plus the whole-history view that tells you what to study next. See all features.
Frequently asked questions
How do I analyze my chess openings?+
Enter your Lichess or Chess.com username and Audit Chess builds an opening tree from your real games, ranked by your win/draw/loss record at every branch. You can walk move by move to see exactly where your results fall off - the point at which a line stops scoring for you - rather than guessing from opening theory.
How is this different from an opening explorer?+
A database explorer shows how millions of other players score in a line. That is theory. This analyzer shows how you score in it - your own results, move by move. A line can be objectively fine and still be a disaster for you because you do not know the resulting middlegames, and only your own games reveal that.
Does it tell me what to fix?+
Yes. Because every branch is tied to your results, the openings quietly costing you points rise to the top, and you can see the exact move where your score collapses. That is the move to study - usually the first position you reach without a plan.
Can I use it to prepare against an opponent?+
Yes. Point it at an opponent's username instead of your own and the same tree shows their weakest openings, so you can steer toward the lines where they score worst - matched to your own repertoire.
How many games do I need before my opening stats mean anything?+
A single branch needs enough games under it to be trustworthy - one loss in a line you have played twice is noise, not a leak. Audit Chess ranks branches by your record but shows the sample size at each node so you can tell a real 20-game problem from a fluke. A few hundred games in an opening family is usually plenty to see where your results fall off.
Does it handle transpositions and different move orders?+
The tree is built from the actual positions in your games, grouped by ECO opening, so lines that arrive at the same structure through different move orders are read as the same opening rather than scattered across unrelated branches. That is what lets it tell you the London System is costing you points regardless of how you got there.
Audit Chess is free and not affiliated with Chess.com or Lichess.