Hornbook

Terms of Use

Official version, effective 18 October 2026

These Terms are an agreement between you and Nguyen Phuong Ngoc ("we", "us") about the Hornbook app and its content packs. By installing or using Hornbook you accept them. If you do not accept them, do not use the app.

1. Study only

Hornbook is for study away from the table.

  • Use it before and after your sessions to review spots and practice.
  • Do not use Hornbook at any point during a session or tournament you are playing, online or in person, until it has ended.
  • Many poker sites and tournaments ban charts, solvers and similar tools while a game is in progress. Breaking those rules can cost you your account and your winnings.
  • Hornbook is not connected to any poker site or software and does not read your screen.

You must not use Hornbook, or anything shown in it, to help make decisions in a game while that game is in progress. You are responsible for following the rules of every site, club and tournament where you play. Using Hornbook against this section is a breach of these Terms (section 9).

2. Who may use Hornbook

You must be at least 18 years old, and old enough to agree to these Terms where you live. Hornbook is a study tool. It does not offer gambling, real-money play or prizes.

3. Licence, not sale

We grant you a personal, non-exclusive, non-transferable, revocable licence to use Hornbook and the packs you are entitled to, on devices you own or control, for your own non-commercial study, under these Terms and the rules of the store you got it from. The app and its content are licensed to you, not sold.

4. Protecting the content

The charts, drills and other content are the result of substantial work. You must not, and must not help anyone else to:

  1. copy, extract, export, screenshot in bulk, publish, share, sell or otherwise redistribute charts, frequencies, packs or pack keys, in whole or in substantial part;
  2. access the app, the pack files or our key service by automated means, or request pack keys other than through the app for your own active subscription;
  3. reverse engineer, decompile, decrypt or modify the app or its packs, or get around its content protection, except to the extent the law where you live allows this despite this restriction;
  4. use the content to build or train another product or service.

5. Free features and Pro

Free features include the heads-up chip-EV charts at every stack depth and 10 drill hands per day. Pro adds the multiway and ICM charts, unlimited drills, leak tracking and spaced repetition. We may add, update or remove content through pack updates. Features and content may differ between app versions.

6. Subscriptions and free trials

  • Pro is an auto-renewing subscription with three plans: monthly (USD 9.99), every 6 months (USD 49.99) and yearly (USD 79.99). The price in your currency is shown in the store before you buy and may differ from these amounts.
  • The 6-month and yearly plans start with a 7-day free trial. The monthly plan has no trial. The store decides whether you are eligible for a trial, usually one per account.
  • Payment is charged to your Apple ID or Google account when you confirm the purchase, or when the trial ends.
  • The subscription renews automatically for the same period and price unless you cancel it at least 24 hours before the end of the current period. Your account is charged for the renewal within the 24 hours before the period ends.
  • If you cancel during a trial, you are not charged. On the App Store, any unused part of a free trial ends when you buy a subscription.
  • Manage or cancel your subscription in your App Store account settings or in Google Play under Payments and subscriptions. Deleting the app does not cancel the subscription.
  • Refunds are handled by Apple or Google under their refund policies.
  • If we change a price, the store tells you in advance as its rules require, and you can cancel before the new price applies.
  • Pro works offline. The app re-checks your subscription with the store when it can. If it cannot check for a long time, or the subscription has ended, Pro features stop until it is confirmed again. Free features and your study data are not affected.

7. No guarantee of results

The charts come from solver runs and models with stated assumptions, such as stack depths, bet sizes, the payout structure used for ICM and a convergence target. They are study material, not advice for any particular game, and they may contain gaps or errors. We do not promise that using Hornbook will improve your results or win you money. Poker involves risk; decisions in your games are yours.

8. Privacy

Our Privacy Policy explains what leaves your phone: https://hornbook.study/privacy/.

9. Breach

If you break section 1 or section 4, your licence ends automatically and you must stop using Hornbook and delete it. Your rights under the law of your country, and the store's refund rules, still apply. Sections 4, 7, 9, 10, 11 and 12 continue after the licence ends.

10. Ownership and notices

Hornbook, its name, design, software and content belong to us or our licensors. Open-source components are used under their own licences, listed in the app under Settings, Open-source licenses. Hornbook is not affiliated with any poker site or tournament series.

11. No warranty

To the extent the law allows, Hornbook is provided "as is" and "as available", without warranties of any kind, including fitness for a particular purpose, accuracy of the content and uninterrupted availability. Some countries do not allow these exclusions; there they apply only as far as allowed.

12. Limitation of liability

To the extent the law allows, we are not liable for indirect or consequential loss, lost winnings or profits, loss of data, or account closures or penalties imposed by poker sites or tournaments. Our total liability is limited to the amount you paid for Hornbook in the 12 months before the claim. Nothing in these Terms limits liability that cannot be limited by law.

13. App Store terms

If you got Hornbook from the App Store: these Terms are between you and us, not Apple. Apple is not responsible for Hornbook or its content, has no obligation to provide maintenance or support, and, to the extent the law allows, has no other warranty obligation; if Hornbook fails to conform to an applicable warranty, you may notify Apple, which may refund the purchase price. We, not Apple, are responsible for handling any claims about Hornbook, including product liability, legal compliance, consumer protection and intellectual property claims. You confirm that you are not in a country subject to a US government embargo and are not on a US government list of prohibited or restricted parties. Apple and its subsidiaries are third-party beneficiaries of these Terms and may enforce them against you. If you got Hornbook from Google Play, the Google Play Terms of Service also apply.

14. Changes

We may update these Terms. We will post the new version here with a new effective date and, for material changes, describe them in the release notes of the next app version. Continuing to use Hornbook after that means you accept the new Terms.

15. Governing law

These Terms are governed by the laws of Vietnam, without affecting the mandatory consumer protection rules of the country where you live.

16. Contact

Nguyen Phuong Ngoc, Apartment 1411, Block CT1 A10 Nam Trung Yen Condominium, Yen Hoa Ward, Hanoi, Vietnam 11213, [email protected]