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Privacy Policy

// LEGAL PROTOCOL · ZERO DATA COLLECTION · EFFECTIVE SEPTEMBER 14, 2026

At StackCalc, we believe mathematics is personal, foundational, and should never be accompanied by surveillance, telemetry, or advertising. Whether you are using StackCalc32 on iOS, iPadOS, or Apple Watch, or following the physical calculator project, we collect zero personal data.

1. Zero Data Collection

  • No Personal Information: We do not collect names, email addresses, phone numbers, physical addresses, or any personally identifiable information (PII).
  • No Analytics or Telemetry: We do not track keystrokes, calculation frequency, app session length, feature adoption, or user workflows.
  • No Device Identifiers: We do not read or transmit IDFA (Identifier for Advertisers), IDFV (Identifier for Vendors), MAC addresses, or IP addresses.
  • No Diagnostics or Crash Reports: We do not bundle third-party crash tracking or diagnostic SDKs.
  • No Biometrics or Health Data: While running standalone on Apple Watch, StackCalc does not access Apple Health, heart rate sensors, workout data, or any biometric sensors.

2. 100% Local On-Device Computation

Every calculation, stack operation, variable memory register, equation, and statistical curve is evaluated exclusively within the local memory of your device:

  • RPN Stack & Memory Registers: Stack levels (X, Y, Z, T, and extended levels), storage registers (0–9, A–Z), and financial registers are stored in local device memory only.
  • Continuous Memory: In accordance with physical calculator behavior, values stored in continuous memory remain preserved locally between app sessions until manually cleared (CLEAR → Continuous Memory) or until the application is removed from your device.
  • No Cloud Synchronization: The application operates completely offline. No network connectivity is required, requested, or used.

3. Third-Party Services & SDKs

The application contains zero third-party software development kits (SDKs), tracking pixels, ad networks, or third-party APIs. We do not sell, rent, monetize, or disclose any user data to third parties under any circumstance.

4. Children’s Online Privacy Protection (COPPA & Global Standards)

StackCalc is designed for learners of all ages, from elementary school students exploring exact fraction manipulatives to university students and professionals performing advanced scientific analysis.

  • Because we do not collect any personal data from any user, we strictly comply with the Children’s Online Privacy Protection Act (COPPA), the General Data Protection Regulation (GDPR), and California privacy laws.
  • We do not require account creation, registration, or login.
  • Children can safely use StackCalc in classrooms, exams, and at home without privacy risk.

5. Website Privacy (stackcalc.io)

Our documentation and storefront website (https://www.stackcalc.io) is hosted via GitHub Pages. Standard server access logs (such as IP addresses and browser user-agent headers) may be automatically processed by GitHub to ensure infrastructure security and deliver the web service. We do not inject tracking cookies or third-party marketing trackers on this documentation site.

StackCalc does not currently process direct physical-product purchases through this website. If a future product links to a named marketplace, that marketplace's privacy policy will describe its checkout, payment, and shipping-data practices.

6. Data Retention and Deletion

Because StackCalc collects no data on remote servers:

  • There is no remote account or database record to delete.
  • To erase all local state, press Yellow Shift + C (CLEAR) → tap CLALL inside the app, or uninstall the application from your Apple device.

7. Changes to This Policy

We may update this Privacy Policy to reflect future updates or legal compliance. Any changes will be posted immediately to this URL (https://www.stackcalc.io/privacy/) with an updated effective date.

8. Contact Information

If you have questions or inquiries regarding this Privacy Policy, please reach out through our public channels: