Free tool
FEN viewer and chess board editor
How it works
Build or paste any position. Place pieces from the palette on the board, edit each of the six FEN fields directly, and the FEN string stays in sync both ways. Paste a PGN to step through the game move by move, then copy a link that carries the exact position.
Pick a piece below, then tap or press Enter on any square. Tapping a square that already holds the selected piece clears it.
Placing a king replaces the other king of the same colour.
The link carries the position, so whoever opens it lands on exactly this board.
The method behind the numbers
Forsyth-Edwards Notation packs a whole position into one line of six fields: piece placement rank by rank from Black’s back rank, side to move, castling rights, en-passant target square, halfmove clock, and fullmove number. This editor renders every field as an editable control, so you can see what each part does instead of treating the string as opaque text.
The editor keeps the rules honest while you work. Castling rights drop automatically when a king or rook leaves its home square, the en-passant target only survives when it is actually reachable, captures and pawn moves reset the halfmove clock, and every move in a loaded game uses proper SAN disambiguation such as Nbd2 versus Nfd2.
Everything runs in your browser; nothing you paste is uploaded anywhere. Malformed FEN strings are rejected with the specific reason, such as which rank has the wrong number of squares or which field is missing, rather than rendering a wrong board.
Frequently asked questions
What does a FEN string look like?
The starting position is rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1. The first long field is the board from Black’s back rank down, then side to move (w), castling rights (KQkq), en passant square (-), the halfmove clock, and the fullmove number.
How do I set up a position by hand?
Pick a colour and a piece in the palette, then tap squares to place pieces. Tapping a square that already holds the selected piece clears it, placing a king replaces the other king of the same colour, and Clear board empties everything so you can start from scratch. The FEN updates after every change.
Does the editor check whether the position is legal?
Yes, at two levels. The six fields are parsed explicitly, so structural mistakes get named errors such as rank 4 has 9 squares or missing side-to-move field. Then the position itself is checked for chess legality: exactly one king per side, no pawns on the first or eighth rank, and an en-passant target only when a capture could actually happen next move.
How do I view a game from a PGN file?
Open the Game viewer tab, paste the PGN, and press Load game. You get the event, players, and result headers when present, a clickable move list, first, previous, next, and last controls, arrow-key stepping, and the position after any selected move on the board. Comments in braces show under the board. Games with variations follow the main line and say so.
How does sharing a position by link work?
Copy link builds a URL ending in ?fen= followed by the current position. Whoever opens it sees exactly your board, including side to move and castling rights. The address bar also tracks your edits live, so bookmarking mid-session saves the position too. The FEN travels entirely inside the link, so there is no account and no database.
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