Free chess tools from Chesslume: rating maths, position analysis, and the small calculations that come up around a game.
- Next Move Calculator — Paste a FEN and get the strongest move from Stockfish 18, with the evaluation and the runner-up candidates.
- Board Editor — Set up any position by hand, get the FEN, and send it straight to the engine.
- Elo Calculator — See what a game is worth before you play it — the rating change for a win, a draw, and a loss.
For a full engine review of a real game, use the free game review instead — it imports your Chess.com or Lichess games and grades every move.
What each tool is for
The Next Move Calculator answers one question about one position: what is the strongest move here? Paste the position as a FEN and Stockfish 18 runs in your browser, then reports its top move, the evaluation it expects and the candidate moves it rejected. It is the quickest way to check an idea from a game, a puzzle or a position you are stuck on.
The Board Editor is for when you do not have a FEN yet. Place pieces on the board, choose whose turn it is and which castling rights remain, and copy the FEN. The editor checks that the position is one a real game could reach, and once it is legal you can send it straight to the engine.
The Elo Calculator shows what a game is worth before you play it. Enter both ratings and a K-factor to see the rating change for a win, a draw and a loss. It makes the arithmetic behind a rating visible, and it is handy for deciding whether a tournament pairing is worth the risk.
Which tool should I use?
- I have a position on the board and want the best move: the Next Move Calculator.
- I only have a diagram or a position in my head: the Board Editor, then send it to the engine.
- I want to know how many points I could win or lose: the Elo Calculator.
- I want to understand a whole game, not one position: the free game review.
Read more
A tool gives you a number or a move; understanding it is a separate skill. Two guides pair well with these pages: what a centipawn evaluation actually means and how Elo and Glicko ratings work. For the engine's limits, see why Stockfish shows the best move but not the plan.