Next Chess Move

Get the best move in any position, drawn on the board and explained in words.

By Nethanel Bar, Co-founder & CEO

Last updated August 29, 2026

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The best move, and the reason for it

A chess engine looks at a position and answers one question: of all the legal moves, which one leaves me best off after both sides play well? This one runs entirely inside your browser. Place the pieces or paste a FEN, press nothing, and the arrow appears on the board with the evaluation beside it, the line it expects, and the two or three next-best moves for comparison.

What makes it worth using rather than any other move calculator is the sentence underneath. Being told that Nf7 is best teaches you nothing you can use next game; being told that the knight on f7 attacks the king and the rook at the same time - and that this pattern is called a fork - is a thing you will spot yourself in a month. Every reason on the page is read off the position, not generated from the score, and each one links to the page that teaches the idea.

Nothing is behind a sign-up and nothing leaves your machine: the search runs on your own processor in a background thread, which is also why the deepest setting is free. The engine is Coddy's own - written for the chess course, the same one the bots on the play page use - so the depth, the number of positions it looked at and the time it took are all printed under the answer rather than hidden.

How to read what the engine tells you

The evaluation is in pawns, always from White's point of view: +1.00 means White stands a pawn better, -2.50 means Black is clearly winning, 0.00 means the position is balanced.
#3 means forced mate in three moves, whatever the defence. A minus sign in front means the side to move is the one being mated.
The line is what the engine expects if both sides play its choices. It is a prediction, not a promise - your opponent is free to play something worse.
The other moves are listed with their own evaluations so you can see the size of the mistake: a move at -0.20 is a matter of taste, a move at -3.00 loses a piece.
Depth is how many moves ahead it searched. More depth changes the answer in sharp positions and almost never in quiet ones, which is why the fast setting is usually enough.

How to find your next chess move

Get your position onto the board
Three ways in. Play the moves of your game on the board as it stands, drag pieces around in Set up position, or paste the FEN - or the whole PGN - into the field under the board and press Load.
Say whose move it is
The To move toggle is the question the engine is answering: the best move for White and the best move for Black are two different answers to two different positions. Getting this wrong is the one mistake that makes a calculator look broken.
Read the move, then the reason
The arrow is the move, the number is the evaluation, and the sentences below say what the move actually does. If the reason names a tactic, follow the link - that pattern is the transferable part, not this particular move.
Check what you were missing
Press What is the threat? to see the move your opponent would play if you did nothing. Most blunders below club level are not missed wins, they are missed threats, and this is the view that shows them.

What the evaluation number means

Engine evaluations are in pawns and always written from White's side, so the same number means the same thing whoever is to move.

Evaluation	Reads as	In practice
0.00 to ±0.30	Equal	Nobody has anything. The game is decided by what happens next, not by what has happened.
±0.30 to ±0.80	A slight edge	Better squares, a safer king, a bishop against a knight. Worth playing for, not worth counting on.
±0.80 to ±1.50	Clearly better	Usually a pawn, or a real positional bind. Club players win these about as often as they lose them.
±1.50 to ±3.00	Winning if converted	A pawn plus pressure, or an exchange won. Trade pieces, not pawns, and the endgame does the work.
±3.00 and up	A piece or more	Decisive at any level. From here the practical task is to avoid giving it back.
#N	Forced mate in N	The line is not an opinion - it works against every defence. Play the moves in the order given.

Positions worth pasting in

A knight fork the engine explains rather than just plays

FEN

3r3k/8/8/4N3/8/8/8/4K3 w - - 0 1

The knight on e5 has one move that matters. Nf7 lands on a square from which it attacks the king on h8 and the rook on d8 at once - the king has to move, and then the rook goes. The tool names the two targets rather than only drawing the arrow, which is the difference between an answer and a lesson.

A back-rank mate in one

FEN

6k1/5ppp/8/8/8/8/5PPP/R5K1 w - - 0 1

Ra8 is mate: the king cannot step onto f8 or h8 because the rook covers the whole eighth rank, and its own pawns block every escape forward. The evaluation reads #1 instead of a pawn count, because a mate is not worth measuring in pawns. This is the pattern behind more decided club games than any other.

The piece that was already lost

FEN

3rk3/8/8/8/8/8/8/3QK3 w - - 0 1

The white queen and the black rook are staring at each other down the d-file, and it is the queen that is in trouble - it is worth more. The best move takes the queen off the file, and the reason given is exactly that: the piece on d1 was under attack and its new square is not. Noticing this before the engine does is most of what improving at chess is.

Why the number sometimes jumps

FEN

r1bqkbnr/pppp1ppp/2n5/4p3/2B1P3/5Q2/PPPP1PPP/RNB1K1NR b kq - 0 4

White is threatening mate on f7 in one move. Ask for the best move for Black and the engine defends; switch the To move toggle to White and the evaluation leaps, because the same position is a catastrophe for whoever is not allowed to fix it. An engine number is never about the position alone - it is about the position and whose turn it is.

Common mistakes

Leaving the To move toggle on the wrong side. The engine will happily answer the other player's question and the move will look absurd.
Reading the evaluation as a promise. +1.5 means the position is better, not that the game is won - you still have to play the moves.
Playing the engine's move without reading the line. The point of Nf7 might be the rook it wins two moves later; play something else next move and the point is gone.
Setting a position up with a king missing. A chess position needs one king per side before anything can be calculated, and the tool will say so rather than guess.
Expecting the deepest setting to change every answer. In a quiet position the best move is usually found at depth 4 and confirmed at depth 8; depth matters where there are captures and checks.
Treating the engine as a coach. It says which move wins, never why the last one lost - for that, read the reasons and follow them to the pattern behind them.

Next chess move FAQ

How does a chess engine find the best move?

It plays the game out in its head. For each legal move it considers every reply, then every reply to that, a few moves deep, and scores the positions at the end by counting material and how well the pieces stand. Working backwards, it assumes both sides pick their best option - that is the minimax idea - and keeps the move whose worst case is the best. Alpha-beta pruning lets it skip lines that cannot change the answer, which is what makes searching millions of positions a second possible.

What is the best chess move in any position?

There is no single move that is best everywhere - a move is only good or bad relative to the position it is played in. What is true in general is that the best move usually does one of a small number of things: it takes something for free, it creates a threat that cannot be answered, it stops the opponent's threat, or it improves the worst-placed piece. The engine's reasons on this page name which of those is happening.

What is the best opening move in chess?

By engine evaluation, 1.e4 and 1.d4 are the strongest first moves, and 1.Nf3 and 1.c4 are close behind - all four take or fight for the centre. The gap between them is far smaller than the gap between playing any of them and playing them well, which is why opening choice matters much less below club level than knowing what to do on move six.

Is using a chess engine cheating?

During a live game, yes - every chess site's fair-play rules forbid it, and accounts are closed for it, permanently. After the game it is the single best way to learn: go through your own moves, find the ones where the evaluation dropped, and work out what you missed. Puzzles, studies and positions you are curious about are fair game too. Analyse everything, but analyse it afterwards.

Is this as strong as Stockfish?

No, and it does not try to be. Stockfish is a decades-old project with a neural network evaluation and it plays at a level no human will ever reach. This engine is our own, written for the chess course, and plays around 1900-2000 at its deepest setting - stronger than the great majority of club players, which is more than enough to find the best move in any position you are likely to be stuck in. What it has that a Stockfish wrapper does not is that we can explain what it found.

What does the plus or minus number mean?

It is the position's value in pawns, from White's point of view. +1.00 means White is a pawn better off; -0.50 means Black holds a small edge. It is never a percentage or a probability, and it is not a score: it is the material and positional balance the engine expects after the line it shows.

What is a FEN, and where do I get one?

FEN is a single line of text describing a position: the pieces rank by rank, whose move it is, the castling rights, and the en-passant square. Every chess site can produce one - on chess.com and Lichess it is in the analysis board's share or export panel. Paste it into the field under the board here and the position appears exactly as it stood.

Can I paste a whole game instead?

Yes. Paste the PGN - the numbered list of moves - into the same field and the board jumps to the position the game ended in, which is usually the one you wanted to ask about. From there you can take moves back with Undo and ask about any earlier position.

Why does the engine sometimes give up a piece?

Because material is not the only thing that counts. A sacrifice is offered when the position it leads to is worth more than the piece - an exposed king, an unstoppable pawn, a mating net. When that happens the reason on the page says so explicitly rather than pretending a capture was won, and the line below shows what the piece bought.

Does it run on a phone?

Yes. The search runs in a background thread so the board stays responsive, and a phone will simply take a little longer at the deepest setting. Nothing is uploaded: if you close the tab, the position goes with it.

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