Question 1

What is ChessIQ and who is it for?

Accepted Answer

ChessIQ is for players who want to review their games, find the moves that changed them, and revisit positions they actually reached.

Question 2

Do I need to create an account to use ChessIQ?

Accepted Answer

No. You can use ChessIQ without creating an account.

Question 3

Which chess platforms does ChessIQ support?

Accepted Answer

ChessIQ supports both Chess.com and Lichess.

Question 4

Can I paste a PGN directly instead of looking up a username?

Accepted Answer

Yes. You can paste a PGN directly, upload a PGN file, or import from supported Chess.com and Lichess links.

Question 5

How do I start my first game review?

Accepted Answer

Bring in a game by username, PGN, file, or link, then open it in Analyze.

Question 6

Does ChessIQ work on mobile?

Accepted Answer

Yes. ChessIQ works on mobile browsers as well as desktop.

Question 7

What engine does ChessIQ use for analysis?

Accepted Answer

ChessIQ uses Stockfish 18.

Question 8

Where does the analysis run — on your servers or my device?

Accepted Answer

Analysis runs on your device, in your browser.

Question 9

How deep does Stockfish analyze each position?

Accepted Answer

ChessIQ does not use one fixed depth for every move. It uses presets for the initial pass, then can continue deepening analysis as needed.

Question 10

Why does analysis speed vary between devices?

Accepted Answer

Because the engine runs locally. Faster devices usually analyze deeper and stabilize evaluations more quickly than slower ones.

Question 11

Can I adjust the engine depth or analysis settings?

Accepted Answer

You can choose analysis presets. ChessIQ handles the deeper engine behavior from there.

Question 12

Does analysis quality differ between desktop and mobile?

Accepted Answer

The engine and scoring model are the same, but mobile devices are often slower. That means deeper analysis may take longer to settle on mobile.

Question 13

Why do engine evaluations sometimes change as depth increases?

Accepted Answer

Because deeper search can reveal tactics, defensive resources, or stronger continuations that were not visible earlier. That is normal.

Question 14

How is move accuracy calculated?

Accepted Answer

Move accuracy is based on centipawn loss using a curve that keeps small misses from being over-penalized while making larger mistakes matter much more.

Question 15

What does game accuracy mean, and how is it different from move accuracy?

Accepted Answer

Move accuracy is the score for a single move. Game accuracy is a weighted average of the moves that count toward the final score.

Question 16

Why do forced moves not count toward my accuracy score?

Accepted Answer

Because there was no real decision to grade. Forced moves are shown, but they do not count toward aggregate accuracy.

Question 17

Why do moves in already decided positions count less?

Accepted Answer

Because easy cleanup moves in winning or losing positions can make a game look cleaner than it really was. ChessIQ downweights those moves so the final score stays more honest.

Question 18

What’s the difference between a Mistake and a Blunder?

Accepted Answer

A Mistake is a significant error. A Blunder is a much larger one.

Question 19

What does “Brilliant” mean? Is it just low centipawn loss?

Accepted Answer

No. Brilliant is not just “low centipawn loss.” It is reserved for rare moves with real tactical value, usually in positions where the move stands out for more than just being accurate.

Question 20

What does “Great” mean versus “Best”?

Accepted Answer

Best means the strongest move. Great is a stronger contextual label for a move that was especially important in the position, often because weaker alternatives failed badly.

Question 21

What is a “Miss” label?

Accepted Answer

A Miss means there was a real opportunity available, but the move played did not take it.

Question 22

Why did I get a low accuracy score even though I felt I played well?

Accepted Answer

Because accuracy measures closeness to the engine’s best move, not how comfortable or practical the game felt. A couple of large mistakes can drag the score down quickly.

Question 23

Why can two games with similar mistakes have different accuracy scores?

Accepted Answer

Because timing and context matter. The size of the mistakes, whether moves were forced, and whether the position was already decided all affect the final number.

Question 24

Where do saved positions come from?

Accepted Answer

They come from your own reviewed games.

Question 25

Do I need to review a game first before saved positions are available?

Accepted Answer

Yes. Saved positions come from games you have already reviewed.

Question 26

How many saved positions are created per game?

Accepted Answer

Usually a few, depending on what the game contains. Not every game produces the same number.

Question 27

Is position progress saved between sessions?

Accepted Answer

Yes. Position progress is stored locally in your browser.

Question 28

Can I revisit positions I’ve already reviewed?

Accepted Answer

Yes. Reviewed positions can still come back as part of your review follow-up.

Question 29

Where are my reviewed games stored?

Accepted Answer

They are stored locally in your browser.

Question 30

What happens to my data if I clear my browser cache?

Accepted Answer

You may lose your saved ChessIQ data, including reviewed games, saved-position progress, and preferences. Export a backup first if you want to keep it.

Question 31

Can I export my reviewed games?

Accepted Answer

Yes. You can export your saved data.

Question 32

Can I import a backup on a different device or browser?

Accepted Answer

Yes. You can export a backup and import it elsewhere.

Question 33

What’s included in an archive export?

Accepted Answer

Your saved review data and supported local backup data.

Question 34

How do I delete all my ChessIQ data?

Accepted Answer

Use the Your Data page and choose Clear Everything, or clear your browser storage manually.

Question 35

If I switch browsers, will my archive carry over?

Accepted Answer

No, not automatically. Your archive is local to that browser. To move it, export a backup and import it in the new browser.

Question 36

What does the Stats page track?

Accepted Answer

It tracks patterns from your reviewed games, including results, accuracy, color splits, time controls, openings, trends, and recurring weaknesses.

Question 37

How many games do I need reviewed before stats are meaningful?

Accepted Answer

A few games can show early hints. A larger sample makes the patterns more trustworthy.

Question 38

Does ChessIQ track performance by opening, time control, or color?

Accepted Answer

Yes.

Question 39

Does ChessIQ upload my games to a server?

Accepted Answer

Core analysis runs locally in your browser. When you import public games from Chess.com or Lichess, ChessIQ only makes the requests needed to fetch those games.

Question 40

Does ChessIQ store my Chess.com or Lichess password?

Accepted Answer

No. ChessIQ does not ask for or store your password.

Question 41

What data does ChessIQ collect about me?

Accepted Answer

Most core data stays in your browser, including reviewed games, saved-position state, and preferences. ChessIQ may also use anonymous analytics and performance tools to improve the site.

Question 42

Does ChessIQ use tracking cookies or advertising?

Accepted Answer

No advertising and no marketing tracking cookies.

Question 43

What is Vercel Analytics and what does it collect?

Accepted Answer

It provides anonymous, aggregated usage data so broken or confusing flows are easier to spot.

Question 44

Why does ChessIQ need my IP address at all?

Accepted Answer

Only for basic server-side rate limiting and abuse prevention on requests that need it.

Question 45

How do I remove all data ChessIQ has stored?

Accepted Answer

Use the Your Data page and clear it from there.

Question 46

Can I use ChessIQ without an internet connection?

Accepted Answer

Some parts, yes. If the app and engine files have already been cached, you can still use saved local features offline.

Question 47

Does the full app work offline, or just some features?

Accepted Answer

Just some features. Internet-based imports and uncached pages still need a connection.

Question 48

How does ChessIQ load so fast after the first visit?

Accepted Answer

Because it caches the app shell and engine files after the first load.

Question 49

Is ChessIQ free?

Accepted Answer

Yes. ChessIQ is free to use.

Question 50

Are there any analysis limits or daily caps?

Accepted Answer

No. Full analysis remains available without a daily cap.

Question 51

Is there a paid tier?

Accepted Answer

No paid tier is active. ChessIQ is currently a free utility: Patterns, Statistics, saved positions, and core single-game analysis are available without an account.

Question 52

How does ChessIQ cover its costs if it’s free?

Accepted Answer

Keeping core analysis on your device helps keep infrastructure costs low enough for ChessIQ to remain a lightly maintained free utility.

Question 53

How is ChessIQ different from Chess.com’s game review?

Accepted Answer

ChessIQ uses browser-local analysis, clear scoring notes, local history, and saved positions from your own games without requiring an account.

Question 54

How is ChessIQ different from Lichess’s analysis board?

Accepted Answer

ChessIQ is more structured around review: import a game, see the key swings, save useful follow-up positions, and build stats from reviewed history.

Question 55

Does ChessIQ use the same scoring method as Chess.com accuracy?

Accepted Answer

No. ChessIQ uses its own scoring model.

Question 56

Why does my ChessIQ accuracy differ from my Chess.com accuracy for the same game?

Accepted Answer

Because the scoring methods are different. Different formulas and weighting rules can produce different numbers for the same game.

Question 57

Why does analysis seem stuck or not starting?

Accepted Answer

Usually it is because the engine is still initializing, the device is slow, or the app needs a fresh reload. If you are offline and the engine has not been cached yet, analysis may not start until you reconnect.

Question 58

What browsers does ChessIQ support?

Accepted Answer

ChessIQ is built for modern browsers that support WebAssembly, Web Workers, and browser storage.

Question 59

Does ChessIQ support chess variants?

Accepted Answer

Standard chess is fully supported. From-position analysis is supported. Chess960 can be analyzed, but support is more limited than standard chess. Other variants are not currently supported.

Question 60

What happens if I close the tab mid-analysis? Is progress lost?

Accepted Answer

If you close the tab before analysis is fully saved, in-progress work may be lost.

Question 61

Why is my old analysis showing a different score than a fresh re-analysis?

Accepted Answer

Because deeper search can change evaluations, and newer analysis passes may refine older results.

Frequently asked questions

Getting Started

Analysis & Engine

Scoring & Move Labels

Saved Positions

Archive & Data

Statistics

Privacy & Security

Offline Use

Access & Costs

Comparison / Context

Technical / Edge Cases