Stockfish Online
Stockfish 19 in your browser — analyse any position, or play against the engine at the strength you choose. Nothing to install.
Mid-game and just need the next move? The chess next move calculator runs the same engine in one click.
Smart Tactics. Human Mode. Full 3650 power.
Train the patterns that win games, and get suggestions you can actually play — not engine lines you can't reproduce.
Play Against Stockfish
Each of these is Stockfish itself, held to a real rating with the engine's own UCI_Elo setting — except Salazar, which is Stockfish with nothing held back.
Below 1320 Stockfish cannot be asked to play weaker, so the beginner bots are built differently — the full ladder of 11 levels explains how.
What's Free, and What Pro Adds
| Feature | Free | Pro |
|---|---|---|
| Analysis strength | Up to 800 | Full Stockfish 19 (3650, depth 22) |
| Play against Stockfish | Up to 2600 ELO | Up to 3650 ELO |
| AI explanation of the move | Daily allowance | Unlimited |
| Set up by board, FEN or PGN | ||
| Screenshot to position |
See Pro for everything it includes.
Which Stockfish Is This?
Stockfish 19, the version released on September 5, 2026. It tests about 44 ELO stronger than Stockfish 18 and sits around 3690 on the CCRL standard list, the strongest open-source chess engine there is.
It is compiled to WebAssembly and runs inside your browser tab. The page opens first and the engine loads behind it, so the board is usable straight away and analysis begins the moment Stockfish is ready. Your positions are searched on your own machine.
Strength settings confuse people because "level" means something different on every site. Stockfish's own Skill Level runs 0 to 20 and its UCI_Elo runs 1320 to 3190; what ELO each Stockfish level plays at has the full table. For an engine that runs without a browser, the desktop app ships a native build that works offline.
Frequently Asked Questions
Is Stockfish online free here?
Yes. Analysis is free up to 800 strength, and you can play free against Stockfish-calibrated bots up to 2600 ELO. Pro unlocks the full engine — 3650 strength at depth 22 — plus the 3 strongest bots and unlimited AI explanations.
Which version of Stockfish is this?
Stockfish 19, released on September 5, 2026 and about 44 ELO stronger than Stockfish 18. It runs as WebAssembly inside your browser, so the engine's search happens on your own device.
How strong is Stockfish 19?
Around 3690 on the CCRL standard rating list — roughly 800 points above Magnus Carlsen's peak of 2882. At full strength no human wins a serious game against it.
Can I play against Stockfish?
Yes. 7 of the bots are Stockfish set to a real rating with its UCI_Elo option, from 1400 up to 3190, and Salazar is Stockfish with no limit at all. Pick one from the list on this page.
Do I need to download anything?
No. The engine loads in the background once the page is open, and your first analysis starts as soon as it is ready. If you want Stockfish outside the browser, the desktop app runs a native build that works offline.
Why does Stockfish's strength setting stop at 3190?
UCI_Elo is a limiter for making the engine play weaker, and its range is 1320 to 3190. Full strength is not a higher setting — it is the limiter switched off, which is what the top level here does.