Privacy policy

Numlight ("we", "us") runs numlight.com. This policy explains what information we handle and why. The short version: our calculators run in your browser, we don't ask who you are, and we don't sell data.

Calculators

The numbers you type into a calculator are processed on your own device. They are not sent to our servers. If you use the "Share" button, your inputs are placed in the page link so whoever opens the link sees the same numbers — only share links you're comfortable sharing.

AI features

When "Ask Numlight" or "Explain my result" is available and you choose to use it, the text of your question and the calculator inputs needed to answer it are sent to our server and to our AI provider, Anthropic, to generate the answer. Please don't include your name, account numbers or other personal details in questions. We don't store the content of questions or answers. Anthropic processes this data under its commercial terms and does not use it to train its models.

To prevent abuse and control costs we keep a short-lived count of AI requests per IP address. These counters are held in memory and reset within a day.

Server logs

Like most websites, our web server records basic technical information for each request — IP address, date and time, page requested, browser type and referring page. We use these logs to keep the site secure and running, and delete them after a limited period.

Hosting, security and analytics

We use Cloudflare to deliver the site quickly and protect it from attacks. Cloudflare processes technical request data such as IP addresses to do this, under its own privacy policy. To understand which pages are useful, we use Cloudflare Web Analytics, which counts visits without cookies and without tracking you across sites.

We don't set advertising or tracking cookies. If that changes — for example, advertising that keeps the site free — we will update this page first and, where the law requires, ask for your consent.

Accounts and children

There are no accounts. Numlight is a general-audience site not directed at children under 13, and we don't knowingly collect their information.

Your rights

Because we don't keep personal profiles, there is usually nothing tied to you to access or delete. Residents of California and other states with privacy laws may still contact us with any request, and we'll respond as the law requires. We do not sell or share personal information for cross-context behavioral advertising.

Changes and contact

We'll post any changes here with a new "last updated" date. Questions: [email protected].