# Privacy > The Chess Calculator has no login, runs Stockfish in your browser, and does not upload positions. URL: Last updated 16 September 2026. ## No accounts There is no login and no account. The calculators work without an email address. ## Analysis stays in the tab The best-move calculator runs Stockfish 18 as WebAssembly in the browser. A FEN you paste or a position you set on the board is not uploaded to our servers. ## Game imports Importing a Chess.com or Lichess game fetches the public PGN from that site so the engine can run here. No copy is kept after the response is sent. Private games stay on those sites. ## What the browser stores Choosing Light or Dark saves that choice under the localStorage key `tcc-theme`. Clearing the site's data removes it. ## Analytics On thechesscalculator.com we load Google Analytics 4, measurement ID `G-ZLPH1X23VE`, to see which pages people open. That script may set first-party cookies such as `_ga`. Positions, FENs, and engine analysis are not included in our custom analytics events. We also use Umami and OpenPanel, both hosted on our own server, to count pageviews, referrers, outbound link clicks, and calculator actions. Neither sets analytics cookies. We exclude URL query strings and fragments from their page tracking so shared board positions are not recorded in analytics. ## Contact