Privacy Policy
Effective October 19, 2026
This Privacy Policy explains how Block Reaction ("we," "us," or "our") collects, uses, and shares information in connection with the KellyCalc mobile application (the "App") and the website on which this policy appears (the "Site," and together with the App, the "Services"). Questions can be sent to info@truecost.tax.
1. Summary
- KellyCalc does not require an account. We do not ask for your name, email address, or phone number.
- Your settings, scenarios, and saved ideas are stored on your device. We do not operate a server that stores them.
- The App sends usage analytics to PostHog. Some events include figures you enter or the App calculates, such as your bankroll and the name you give a saved idea. These events are tied to a random identifier, not to your name or Apple Account.
- We do not track you across other companies' apps or websites, show ads, or sell personal information.
- The Site does not use analytics or advertising cookies.
- Apple processes all payments. We never receive your payment details.
2. Information stored on your device
The App stores the following on your device: your bankroll and default settings (currency, odds format, input view, Kelly fraction, and allocation cap), the scenarios you enter, saved ideas and their names, your onboarding answers, and how many free calculations you have used this week. Deleting the App removes this information. It may also be included in device backups you make, such as iCloud Backup, which Apple handles under its own terms.
3. Information we collect
3.1 Analytics from the App
The App sends event data to PostHog, our analytics provider, so we can understand how the App is used, fix problems, and decide what to build. PostHog assigns each installation a random identifier. Events include:
- Onboarding: which screens you view, whether you mainly size investments or bets, your currency and odds format, and how you heard about the App.
- Calculator use: which input view you use, when you add, edit, or delete scenarios, and when you run a calculation, including the bankroll and number of scenarios. Scenario labels, odds you type, and individual prices and probabilities are not sent.
- Results: the calculated Kelly fraction and expected return, the Kelly fraction you choose, and summary statistics from Monte Carlo simulations.
- Saved ideas: when an idea is saved, loaded, or deleted. Saving sends the idea's name, bankroll, Kelly fraction, and expected return.
- Tutorials and settings: which tutorial steps you view or skip, and which defaults you change. A changed default bankroll is recorded without the amount.
- Purchases: when the upgrade screen is viewed, when a purchase or restore starts, completes, is pending, is canceled, or fails, and whether Unlimited is active.
- App and device: when the App is installed, opened, or closed, and the device model, operating system, App version, language, and similar technical information that the analytics software collects automatically.
Because saved-idea names are free text, avoid putting personal information in them.
3.2 Information from the Site
The Site has no forms, analytics, or advertising. Our hosting provider records standard server logs, such as IP address, requested page, date and time, and browser information, to deliver and secure the Site.
3.3 IP address
When your device connects to PostHog or our hosting provider, your IP address is transmitted as part of that connection and may be used to infer an approximate location, such as country or city. The App does not request access to Location Services.
3.4 Purchases
Purchases are processed by Apple through the App Store. Apple provides the App with the information needed to confirm your purchase, such as the product and transaction identifiers. We do not receive your name, payment card, or billing address.
3.5 Information you send us
If you email us or post on our feedback board, we receive what you choose to send, such as your email address and message, and use it to respond and improve the App. The feedback board is hosted by Fider under its own privacy policy.
4. How we use information
- Provide and support the Services, including confirming your purchase;
- Understand how the Services are used and improve them;
- Diagnose errors and performance problems;
- Respond to you when you contact us;
- Protect the security and integrity of the Services; and
- Comply with legal obligations and enforce our Terms of Use.
We do not use your information to serve you advertising.
5. Legal bases (EEA and UK)
If you are in the European Economic Area or the United Kingdom, we process personal data based on our legitimate interests in operating and improving the Services, to perform our contract with you when you buy Unlimited, and to comply with legal obligations.
6. How we share information
| Recipient | Purpose | Information |
|---|---|---|
| PostHog, Inc. | Product analytics for the App, hosted in the EU | Events, device information, random identifier, IP address |
| Our website hosting provider | Serving and securing the Site | Server logs |
| Apple Inc. | App distribution and purchases | As governed by your relationship with Apple |
We may also disclose information if required by law, to protect the rights or safety of our users or others, in connection with a merger, acquisition, or sale of assets, or with your consent. We do not sell personal information or share it for cross-context behavioral advertising.
7. Tracking
The App does not access Apple's advertising identifier, does not show the App Tracking Transparency prompt, and does not combine its data with data from other companies for advertising. The App contains no ads.
8. Retention and security
Information on your device stays there until you delete it or the App. We keep analytics data for as long as it is useful for the purposes above, and no longer than 24 months. Connections between the App and PostHog are encrypted. No method of transmission or storage is completely secure.
9. International transfers
We are based in the United States. App analytics are stored by PostHog in the European Union. Our providers may process information in the United States or other countries, where data protection laws may differ from those of your country.
10. Your choices and rights
You can delete saved ideas in the App, or delete the App to remove everything it stores on your device. Depending on where you live, including the EEA, UK, California, and other U.S. states with privacy laws, you may have the right to access, correct, delete, or receive a copy of personal information we hold about you, to object to or restrict its processing, and not to be discriminated against for exercising these rights. EEA and UK residents may also complain to their local data protection authority.
To make a request, email info@truecost.tax. Because we do not know your identity, we may ask for details that help us find your records, such as the approximate dates you used the App and your device type, and we may be unable to act on a request if we cannot reasonably link data to you.
11. Children
The Services are intended for adults and are not directed to children under 16. If you believe a child has given us personal information, contact us and we will delete it.
12. Changes to this policy
We may update this Privacy Policy. When we do, we will post it here and change the effective date above. For material changes, we will also give notice, such as in the App's release notes.
13. Contact us
Contact Block Reaction at info@truecost.tax.