Privacy Policy

The short version

• You do not need an account, and we do not ask for your name or email to use the calculators.
• We run no analytics, no advertising and no tracking scripts. We set no cookies unless you choose to sign in to save results, an optional feature that is currently switched off.
• Most calculators run entirely in your browser: the numbers you type are not sent to us.
• If that ever changes, for example if we add advertising, this page will be updated before it happens.

Who is responsible

CalculationTime is run by William Turner in Coffs Harbour, New South Wales, Australia. You can contact us at:

William Turner, CalculationTime
354 Harbour Drive, Coffs Harbour NSW 2450, Australia
info@calculationtime.com

What is stored in your browser

A few calculators remember your preferences in your browser’s local storage, for example the light or dark theme, clock display settings, saved bookmarks and whether you have dismissed a tip. This information stays on your device, is never sent to us, and can be cleared at any time from your browser settings.

The site also keeps a small offline copy of a few core pages and icons in your browser so it loads faster on a return visit. It holds no personal information and is cleared along with your other site data.

Optional sign-in to save results

Some calculators are built to offer an optional “Sign in with Google to save results” feature. It is currently switched off. If we switch it on, it will stay optional: every calculator will keep working without an account.

If you choose to sign in:

• Google shares your name, email address, profile picture and Google account ID with us. We use them only to show you your own saved results.
• While you are signed in, each result you calculate is saved automatically, together with the numbers you entered, the calculator used and the date. On health calculators those numbers can include details such as weight, height and age.
• Saved results are stored with our database provider, Supabase.
• A cookie or browser storage entry keeps you signed in until you sign out.
• You can sign out at any time, and you can ask us to delete your saved results and account by emailing us. We will do it.

We will update the date at the top of this page when the feature goes live.

Hosting and server logs

The website is hosted by Vercel. Like any web server, Vercel’s systems record technical details of each request, such as your IP address, browser type, the page requested and the time, to deliver the site and protect it from abuse. We do not use these logs to identify or profile visitors. See Vercel’s privacy policy.

Services your browser contacts

• Currency rates. The currency converter fetches exchange rates from the Frankfurter service (api.frankfurter.dev). Your browser connects to it directly, so it sees your IP address. No other details are sent.
• CalculationTime API. Some sky and clock tools, and developers using our public API, request data from api.calculationtime.com, hosted in Germany. Requests may be logged, including IP address, for rate limiting and security.
• Fonts and sky data libraries. A few of our standalone sky instruments load typefaces from Google Fonts and the open-source Astronomy Engine library from jsDelivr, so your browser contacts those services when you open them.
• Links to other websites are covered by those sites’ own privacy policies.

If you email us

We use your email address and message only to reply and to fix or improve the calculators. We do not add you to a mailing list or share your details with anyone.

Your choices and rights

You can ask what information we hold about you, and ask us to correct or delete it, by writing to the contact details above. We handle personal information in line with the Australian Privacy Principles. If you are not satisfied with our response, you can contact the Office of the Australian Information Commissioner at oaic.gov.au.

Changes to this policy

If we change how information is handled, for example by adding analytics or advertising, we will update this page and its date before the change takes effect.