Privacy Policy

Welcome to Ekuation ("Ekuation", "we", "us", "our"). We build free online calculators for finance, health, math, and everyday life. This Privacy Policy explains what information we collect, why we collect it, and how we handle it.

The short version: we collect as little data as possible, we never sell your data, and we use privacy-friendly analytics that don't track you across the web.

If you create an account, we store:

• Account details — your name, email address, and profile picture (if you sign in with Google, Apple, or Facebook, we receive these from your provider).
• Calculator profiles — personal details you choose to save (such as age, height, weight, activity level, or currency preference) so your calculators can auto-fill. You control what you save, and you can delete your profiles at any time.
• Field preferences — your per-calculator display settings (e.g. which unit system to default to).

You do not need an account to use our calculators. If you use Ekuation without signing in, your recently used calculators and any profile data are stored locally in your browser (localStorage) and never sent to our servers.

• Privacy-friendly analytics — we use Plausible Analytics, a lightweight, cookie-free analytics tool. Plausible does not use cookies, does not track you across sites, and does not collect personal information. It tells us aggregate page view counts — nothing more.
• Error reports — we may use Sentry to capture JavaScript errors so we can fix bugs. Error reports may include your browser type, operating system, and the page URL where the error occurred. They do not include personal information.
• Session recordings — when enabled, we may use Microsoft Clarity to understand how people interact with our pages (clicks, scrolls, navigation). Clarity anonymizes data and does not identify individual users.

We do not set any first-party tracking cookies. If you sign in, we use a session cookie strictly to keep you logged in. Third-party tools we integrate (such as Clarity or Google AdSense, when enabled) may set their own cookies — see their respective privacy policies for details.

We use your information to:

• Provide the service — run calculators, save your profiles, and keep you signed in.
• Improve the product — understand which calculators are popular and fix errors.
• Communicate with you — send transactional emails (e.g. magic link sign-in) via Resend. We do not send marketing emails.

We do not sell, rent, or share your personal data with advertisers or data brokers.

Some calculators offer an optional AI-powered chat that explains your results. When you use this feature, your calculation inputs and results are sent to OpenAI to generate a response. We do not send your account details or profile data to OpenAI.

We rely on a small number of third-party services to run Ekuation:

Each service has its own privacy policy. We encourage you to review them if you have questions about how they handle data.

Your data is stored on servers hosted by Hetzner in the European Union. We use encryption in transit (HTTPS) and follow standard security practices to protect your information.

You can:

• Access your data by viewing your account settings and calculator profiles.
• Delete your account and all associated data at any time from your account settings.
• Use Ekuation without an account — no personal data is collected on our servers in that case.

If you are in the EU, you have additional rights under the GDPR, including the right to data portability and the right to lodge a complaint with a supervisory authority.

Ekuation is not directed at children under 16. We do not knowingly collect personal data from children. If you believe a child has provided us with personal information, please contact us so we can delete it.

We may update this Privacy Policy from time to time. When we do, we will update the date at the top. Your continued use of Ekuation after changes are posted means you accept the updated policy.

If you have questions about this Privacy Policy or your data, reach us at [email protected].