プライバシーポリシー — 比率計算ツールの個人情報保護とセキュリティ

At 比率計算ツール (accessible from https://www.ratiocalculator.net), the privacy of our visitors is one of our top priorities. This Privacy Policy document outlines the types of information we collect, how we use it, and how your data is protected when using our free suite of mathematical calculators and educational guides.

1. Client-Side Calculation Privacy (Zero Input Logging)

Ratio Calculator operates on a client-side computation architecture. All mathematical operations — including proportion solving, ratio simplification, greatest common divisor (GCD) reduction, scaling, and unit conversions — run entirely inside your web browser using client-side JavaScript.

• We do not record, store, or transmit the numbers or equations you enter.
• Your input values and calculated results remain private to your local device.
• No user accounts, logins, passwords, or credit card details are ever requested or stored.

2. Log Files & Automated Technical Data

Like standard web services, our hosting servers automatically log non-personally identifiable diagnostic information when you access the website. This data includes:

• Internet Protocol (IP) addresses and general geographic region (country/city level).
• Browser type, version, and operating system.
• Referring/exit URLs and timestamps.
• Pages visited and aggregate time spent per session.

This technical information is used strictly for server maintenance, network security, abuse prevention, and analyzing overall traffic trends. It is never linked to any personally identifiable information.

3. Cookies & Local Storage

Ratio Calculator uses minimal, standard cookies and browser local storage to improve your browsing experience. These are used to:

• Remember interface preferences, such as selected language across our 18 supported locales.
• Maintain session stability and optimize page rendering speed.

You can choose to disable or selectively turn off cookies through your individual browser settings. Please note that disabling cookies may affect some convenience settings.

4. Google AdSense & Third-Party Advertising Disclosures

To keep our calculators 100% free and accessible to everyone worldwide, Ratio Calculator may display third-party advertisements served by Google AdSense and other advertising networks.

• Third-Party Vendors: Google, as a third-party vendor, uses cookies (including the DoubleClick cookie) to serve advertisements based on your prior visits to this website and other websites across the Internet.
• Personalized Advertising: Google's use of advertising cookies enables it and its partners to serve personalized ads to users based on their browsing activity.
• Ad Settings & Opt-Out: Users may opt out of personalized advertising at any time by visiting Google Ads Settings. Alternatively, you can opt out of third-party vendor cookies for personalized advertising by visiting www.aboutads.info.
• Third-Party Ad Networks: Third-party ad servers or networks use technology in their respective advertisements that appear on Ratio Calculator, which are sent directly to your browser. Ratio Calculator has no access to or control over these cookies used by third-party advertisers.

5. Web Analytics

We may use privacy-compliant web analytics services (such as Google Analytics) to monitor aggregate traffic volume, popular calculation categories, and general device compatibility. These tools collect anonymized data without identifying individual users. We use these insights solely to optimize page load speeds and improve our calculator tools.

6. Contact Form & Communications

When you contact us via our Contact Us form or directly by email at hello@ratiocalculator.net, you provide your name, email address, and message content.

• This information is used solely to respond to your specific inquiry, suggestion, or bug report.
• We do not sell, rent, trade, or share your contact details with any third parties for promotional or marketing purposes.

7. Children's Online Privacy Protection (COPPA)

Ratio Calculator provides free educational mathematics tools suitable for students and educators of all ages. We do not knowingly collect or solicit any personally identifiable information from children under the age of 13. If you believe that a child has provided personal information to us, please contact us immediately so we can promptly delete it.

8. Data Security & Encryption

We implement strict technical security measures to protect website access. All traffic to Ratio Calculator is transmitted over encrypted HTTPS/TLS 1.3 connections, preventing interception or tampering of web communication.

9. External Links

Our website may contain links to external sites, educational resources, or partner tools. We do not control and are not responsible for the content, security, or privacy policies of third-party websites. We encourage you to review the privacy policies of any external site you visit.

10. Changes to This Privacy Policy

We may update our Privacy Policy periodically to reflect technological updates, service adjustments, or legal obligations. When updates occur, the revision date at the top of this page will be updated accordingly. Continued use of the website following any changes signifies your acceptance.