Privacy Policy

1. Introduction

Sleep Calculator (“we”, “our”, or “us”) operates this website. This page explains how we handle your information when you use our tool.

This tool runs entirely in your browser — it does not require an account, and all inputs (your chosen time, age group, or nap length) stay on your device. We do not collect or store the times you calculate.

2. Data We Collect

2.1 Google Analytics

We use Google Analytics 4 (GA4) to understand how visitors use the site. GA4 collects anonymised data including:

• Pages visited and how long you stay on each page
• Your approximate geographic region (city-level, not precise location)
• Browser type, device type, and operating system
• Referring website or source that brought you to the site

Google Analytics uses cookies and similar tracking technologies. Google’s privacy policy is available at policies.google.com/privacy.

3. Cookies & Local Storage

• Google Analytics cookies(_ga, _ga_*) — used to distinguish unique users and throttle request rates. These expire after 2 years.
• Local storage— we store your theme preference (light/dark mode) locally in your browser. This data never leaves your device.

You can control cookies through your browser settings. Blocking analytics cookies will not affect the core functionality of the sleep calculator.

4. How We Use Your Data

We use the information we collect to:

• Improve the tool and user experience
• Understand which features are most useful
• Monitor site performance and diagnose technical issues
• Measure traffic and engagement for future content planning

We do not sell your data or share it with third parties beyond the analytics providers listed here.

5. Third-Party Services

• Google Analytics— web analytics (see section 2)
• Google AdSense— contextual advertising. Not currently enabled on this site; if enabled in future, AdSense may use cookies to serve personalised ads. See Google’s advertising policy for details.

6. Your Rights

• Right to opt out — you can opt out of Google Analytics using the Google Analytics opt-out browser add-on

7. Data Retention

Google Analytics data is retained for 14 months before being automatically deleted. We do not store any personal data on our servers.

8. Children’s Privacy

This site is not directed at children under the age of 13. We do not knowingly collect personal information from children.

9. Health Disclaimer

This tool provides general estimates based on published sleep-cycle research and is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. If you have concerns about a sleep disorder or persistent sleep problems, consult a qualified healthcare provider.

10. Changes to This Policy

We may update this privacy policy from time to time. We will notify you of any changes by posting the new policy on this page and updating the “Last updated” date.