Privacy policy
Last updated
This site collects very little. You don’t need an account, there are no sign-up forms, and we don’t collect the numbers you enter into the calculators.
What stays on your device
The calculators save some things in your browser’s local storage so they work the way you expect. This data never leaves your device, and you can clear it at any time in your browser settings.
- Your last inputs (key
rc:last:v1), so the calculator opens where you left off. - Your saved calculations (key
rc:saved:v1), if you choose to save any. - Your vial list (key
rc:vials:v1), if you add vials to the vial tracker. - Your light or dark theme choice (key
color-scheme), if you pick one. - Offline copies of pages. If your browser supports it, the site stores copies of its pages and files so the calculators work without a connection.
The page address
The numbers you type never go into the page address. The calculator remembers them on your device instead, so they come back when you return.
- Share result creates a link that contains your numbers, so the person you send it to sees the same result. Anyone with the link can see them.
- When a share link is opened, the page reads the numbers and removes them from the address straight away, before any statistics or other scripts run. Our host still receives that first request with the numbers in it, like any web request, and it may appear in its server logs.
- When you follow a link to another site, we tell your browser to pass on only our site name, never the full address.
Visitor statistics
We use Vercel Web Analytics and Google Analytics to count visits, and Vercel Speed Insights to measure how fast pages load.
- Vercel Web Analytics and Speed Insights never use cookies.
- Google Analytics outside the EEA, the UK and Switzerland uses cookies (
_gaand_ga_<ID>, kept for up to 2 years). They hold a random ID, so it can tell new visitors from returning ones. They don’t contain your name, email or the numbers you enter. See the cookie policy. - Google Analytics in the EEA, the UK and Switzerland sets no cookies. It sends Google only anonymous pings that aren’t linked to you.
- Google receives your IP address and browser details, like any website you load files from. It uses them to count visits and estimate location. See how Google uses data from sites that use its services. You can block Google Analytics with Google’s opt-out add-on or by blocking cookies in your browser.
- We remove everything after the “?” in page addresses before they are sent, so the numbers you enter never reach these statistics.
- We may count simple actions, like “a calculation was made” or “a result was shared”. These counts never include the numbers you entered.
Hosting and server logs
The site is hosted by Vercel. Like most web hosts, Vercel processes your IP address and browser details to deliver pages and protect the site from attacks. See Vercel’s privacy policy for details.
Emails you send us
If you email us, we use your address and message only to reply and to fix what you report. We don’t add you to any list, and we delete messages we no longer need.
Advertising
The site shows no ads today. When we turn ads on, they will be served by Google AdSense and work like this:
- In the European Economic Area, the UK and Switzerland, Google’s consent banner asks you first. Ads and advertising cookies load only if you agree, and you can change your choice at any time from the privacy settings link the banner adds to the page.
- Elsewhere, Google may show ads that use cookies or similar identifiers to choose and measure ads. You can turn off personalized ads in Google’s ad settings.
- Ads never appear between a calculator’s inputs and its result, and ad providers never receive the numbers you enter.
If you accept cookies in the consent banner, Google Analytics may also start using its cookies. See the cookie policy. We will update this policy on the day ads go live.
Children
The site is not meant for children under 18, and we don’t knowingly collect data from them.
Changes and questions
We will update this page when anything changes, and change the date at the top. For questions, use the contact page.