Privacy policy

What runs where

Editing numbers recalculates the answer on your device. Calculator-use events identify the tool used, not the numbers you type.

Prefilled calculation links contain the inputs in their URL. Anyone with the link can read them. Opening it sends the URL to the site; it may also appear in browser history, server logs and analytics. Do not share confidential numbers.

Cookies

Fathom Analytics does not use cookies. Google Analytics may use cookies and browser identifiers to measure visits. The site also stores your theme choice in browser storage.

Analytics

We use Fathom Analytics and Google Analytics to measure page views, referral sources and calculator interactions. Google Analytics receives page URLs, which can include numbers in shared calculation links. Feedback is handled separately below.

The feedback form

If you send us a message through the feedback form, we receive what you wrote, and — because it is the difference between a bug we can reproduce and one we cannot — your browser and operating system, your screen size, your language and time zone, and the page you were on. Your email address is optional, and is used only to reply to you.

Messages are delivered to our own inbox and to a private team channel. They are not published, sold, or used for marketing.

Hosting and server logs

The site is served by Cloudflare. Like any web server, Cloudflare processes the IP address of every request in order to deliver the page and to block abuse. We do not build profiles from those logs. A submission from the feedback form is rate-limited by IP address for ten minutes, in memory only.

Children

The site is a general-audience tool and is not directed at children. It asks for no personal information from anyone.

Changes

If this policy changes, the date at the top of this page changes with it. There is no mailing list to notify, because there is no mailing list.

Contact

Questions about any of the above go through the feedback form.