Stockfish 19 offline on iPhone, iPad and Mac
For iPhone, iPad and Mac. No account.
- +0.145. a4
- +0.135. O-O
- +0.135. d3
Stockfish is a free, open-source chess engine and the reference for computer analysis. ChessWOW includes Stockfish 19 with its full neural network and runs it directly on your iPhone, iPad or Mac. There is no server in between: positions are calculated on your device, with or without a connection. This page explains what you see on the analysis screen and how to read it.
What "on the device" means
Many chess apps send positions to a server and show the result. ChessWOW does not. The engine is part of the app and uses your device's processor. That has three practical effects. Analysis works in airplane mode, in a basement club room or abroad without roaming. Your positions never leave the device. And the speed depends on your hardware: a recent iPad or Mac reaches a given depth faster than an older iPhone, while the evaluation method is the same on every device.
Reading the evaluation
Stockfish expresses its judgement as a number in pawns, seen from White's side. Positive numbers favour White, negative numbers favour Black. "+1.0" means White's advantage is worth roughly one extra pawn; "-0.5" means Black is slightly better. As a rough rule of thumb:
- Between -0.3 and +0.3: balanced. Both sides have chances.
- Around 0.5 to 1.0: a noticeable edge, often enough to press for a long time.
- Around 1.0 to 2.0: a clear advantage that a strong player usually converts.
- Above 2.0: usually winning, if the stronger side avoids accidents.
When Stockfish finds a forced mate, it shows the mate instead of a number. Keep in mind that an evaluation is about best play from both sides. A position at +1.5 can still be lost in practice if the winning plan is hard to find or the clock is running low. In game reports, ChessWOW shows the evaluation from your point of view, so a positive number always means you were better.
- Balanced
- Edge
- Clear advantage
- Usually winning
Best move and three lines
The arrow on the board shows Stockfish's preferred move. Below it you see up to three candidate lines, each with its own evaluation. Comparing them tells you more than the best move alone:
- Lines close together: several moves are about equally good. Pick the one whose plan you understand.
- A large gap after the first line: only one move holds the position. These are the moments worth memorizing.
- All lines bad: the damage was done earlier. Step back through the moves to find where.
Play any move on the board and the engine recalculates the new position. You can always jump back to where you started.
- +0.145. a4
- +0.135. O-O
- +0.135. d3
Depth: why the numbers move
Stockfish searches deeper the longer it runs. The analysis screen shows the current depth. In quiet positions the evaluation settles quickly; in sharp tactical positions it can jump as the engine discovers a hidden resource. If a line looks surprising, give the engine a few more seconds before drawing conclusions.
Where your positions come from
Every way into ChessWOW ends on the same analysis board: a scanned screenshot or book diagram, a position from the board editor, a game imported from Chess.com or Lichess, or a game you just played against the engine. After a full game, the game report uses the same engine to rate every move.
Use the engine to check your thinking, not to replace it
An engine gives a verdict without an explanation of the plan behind it. The best use is to form your own idea first, write it down or play it on the board, and then compare. Where you agreed with Stockfish, you can trust your judgement more. Where you disagreed, step through the lines until you see what you missed. If you want to test your play under real conditions, play against Stockfish at a level that suits you.
Questions and answers
Is it the real Stockfish?
Yes. ChessWOW includes Stockfish 19 with its full neural network (NNUE). Stockfish is free software under the GPLv3.
Does the analysis need an internet connection?
No. The engine runs on your device. You only need the internet for importing games, downloading the optional endgame tablebases and purchases.
What does +1.2 mean?
White is better by an amount worth a little more than one pawn, assuming best play from both sides. Negative numbers mean Black is better.
Why does the evaluation change while I watch?
The engine is searching deeper. Each new depth can find moves it had not seen before. The depth is shown on the screen.
How many lines does ChessWOW show?
The best move as an arrow and up to three candidate lines with their evaluations.
Is it as fast as a cloud engine?
A server with many processor cores can search faster than a phone. For studying a position, the depth a current iPhone, iPad or Mac reaches in a few seconds is usually more than enough, and it works offline.
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ChessWOW runs on iPhone, iPad and Mac. No account needed.
Download freeChessWOW is free to download. Unlimited analyses and game reports are part of ChessWOW Pro. Depending on the current offer, you can try Pro with a free daily allowance or a free trial. The App Store shows price and terms before you confirm anything.