Terms of use

Last updated November 4, 2026

Chess Calculator is a trainer for calculating chess moves in your head. These terms say what you can expect from us and what we ask of you.

Who we are

Chess Calculator is made and published by Synergy Tecnologia Ltda (CNPJ 51.033.169/0001-89), Rua Vicente Oropallo, 70, São Paulo, SP, 05351-025, Brazil ("we"). You can reach us at luis@synergytec.com.br. By installing or using the app you agree to these terms. If you don't agree, please don't use the app.

Your licence to use the app

We give you a personal, non-exclusive, non-transferable licence to install and use Chess Calculator on devices you own or control, for your own use, under these terms and the rules of the store you got it from. The app, its design and its name belong to us. You may not copy, sell, rent, modify, reverse engineer or redistribute it, except where the law allows it regardless of this clause.

What the app is, and isn't

The app trains calculation with puzzles, drills and ratings. Ratings are estimates from your own attempts and are not an official chess rating. Coach tips are written by an artificial-intelligence model from analysis made by a chess engine; we ground them in that analysis, but they can still be imperfect, and they are not a substitute for a human coach. Nothing in the app is a promise about any result in your play.

Free use and Premium

Puzzles, sessions, modes, ratings, drills, refutations and the daily target are free and work offline. Each install includes five free coach tips. After that, coach tips need Premium, a monthly or yearly subscription sold and billed by the App Store or Google Play under that store's terms, including its rules on free trials, renewal, cancellation and refunds. We don't handle payments or hold your card details. Prices, and any trial, are shown in the store before you buy.

Premium renews automatically until you cancel it in your store account; cancelling stops the next renewal and keeps Premium until the end of the paid period. Restore purchases brings Premium back on a new phone with the same store account. Coach tips have a fair-use limit per day for Premium, and the five free tips belong to an install, so reinstalling the app doesn't grant new ones.

Your data

The app has no account, and your progress stays on your phone. What the app stores, what it sends when you ask for a coach tip, and your choices are described in the privacy policy, which is part of these terms.

Acceptable use

Please don't use the app to break the law, to interfere with the app or the services behind it, to work around Premium or the free-tip limit, or to run automated requests against the coach service. We may stop serving an install that does, and the store may act under its own rules.

Credits and third-party software

Puzzles come from the Lichess puzzle database, which Lichess releases to the public domain (CC0). Analysis is made with Stockfish, free software released under the GNU General Public License version 3; its source code is available at stockfishchess.org. Coach tips are generated with Google's Gemini API. Chess Calculator is not affiliated with Lichess, the Stockfish project, Google, Apple or Chess.com.

Changes to the app and to these terms

We keep improving the app and may change, add or remove features, including with no notice when a change is minor or needed for security. If we change these terms in a way that matters, we'll update the date on this page and say so in the app or in the store listing. Using the app after a change means you accept the new terms.

No warranty

Chess Calculator is provided as it is. To the extent the law allows, we make no warranty that it will be error-free, uninterrupted or fit for a particular purpose. Nothing here limits rights you have as a consumer under the law that applies to you, including Brazil's Consumer Defence Code.

Limitation of liability

To the extent the law allows, we are not liable for indirect, incidental or consequential loss arising from your use of the app, and our total liability for any claim connected with the app is limited to the amount you paid us for Premium in the twelve months before the claim, if any.

Ending the relationship

You can stop using the app at any time by uninstalling it, which also deletes what it stored on your phone; cancel any subscription in your store account. We may end this licence if you break these terms.

Law and disputes

These terms are governed by the laws of Brazil. Disputes go to the courts of São Paulo, SP, Brazil, without prejudice to any mandatory rule that lets you use the courts or consumer bodies where you live. If a clause is found invalid, the rest stays in force.

Contact

Questions about these terms: luis@synergytec.com.br.