Cookieポリシー

最終更新日: 2026年10月

1. Introduction

FOIL Calculator ("we," "our," or "us") is dedicated to providing a transparent, educational tool for algebra learners worldwide. We believe in minimal data footprint and total user privacy. This Cookies Policy explains what cookies and similar local storage technologies are, how we use them on foilcalculator.com ("the Service"), and how you can manage them.

2. What Are Cookies and Local Storage?

Cookies are small data files placed on your browser or device by web servers. They allow websites to remember actions and preferences over a period of time.

Local Storage (HTML5 Web Storage) is a modern web standard that allows web applications to store key-value data directly in your browser. Unlike traditional cookies, local storage data stays on your device and is not automatically sent across the network to web servers with every single HTTP request, making it faster and more private.

3. How We Use Cookies and Local Storage

FOIL Calculator uses only essential and functional storage strictly necessary to provide the website's core features. Here is the complete list of how we use client storage:

• Cookie Consent Status (foil_cookie_consent) — When you click "Accept Cookies" on our homepage banner, we store this preference in your browser's localStorage so that the notification does not disrupt your future study sessions.
• Language & Localization Preference — Used to preserve your selected interface language across your visits so you can read mathematical explanations in your preferred language.
• Client-Side Calculator State — Your binomial inputs and calculation history are processed entirely in memory or temporary session state inside your browser. No mathematical equations or results are ever sent to our servers.

4. No Advertising or Tracking Cookies

We believe learning mathematics should be free from invasive surveillance. Therefore:

• We do not use third-party advertising cookies.
• We do not use cross-site tracking pixels or fingerprinting scripts.
• We do not sell, rent, or monetize your usage data with data brokers.

5. Third-Party Services

To deliver a fast, reliable, and secure experience, we rely on trusted infrastructure providers who operate under strict privacy standards:

• Google Fonts — Used to render high-legibility mathematical typography and modern web fonts. Google Fonts operates without tracking cookies.
• Vercel — Hosts our static application and edge CDN network, utilizing standard server-level logs and technical security measures without profiling individual visitors.
• Web3Forms — Powers our contact form if you voluntarily choose to send us an email inquiry. Form data is transmitted securely over encrypted SSL/TLS connections.

6. How You Can Control Cookies and Local Storage

You have full control over the cookies and storage saved on your device. You can manage or delete them at any time through your browser settings:

• Google Chrome: Settings > Privacy and security > Third-party cookies > See all site data and permissions.
• Mozilla Firefox: Settings > Privacy & Security > Cookies and Site Data > Manage Data.
• Apple Safari: Settings > Safari > Advanced > Website Data.
• Microsoft Edge: Settings > Cookies and site permissions > Manage and delete cookies and site data.

Note: If you clear your browser's local storage, your cookie consent banner will reappear on your next visit to the homepage, as the stored acceptance token will have been removed.

7. Changes to This Cookies Policy

We may update this policy periodically to reflect technical or legal improvements. When updates occur, the "Last updated" date at the top of this page will be revised. We encourage you to review this page occasionally.

8. Contact Us

If you have any questions or feedback regarding our use of cookies or our privacy practices, please reach out through our contact form or email us at hello@foilcalculator.com.