Privacy
Last updated 7 October 2026
The short version
The calculator runs entirely inside your browser. The vial sizes, doses and costs you type are never sent to us, never stored, and never leave your device. We cannot see them.
What we collect
Calculator input: nothing. No numbers you enter are transmitted or saved. Close the tab and they are gone.
Analytics: Google Analytics, only if you allow it. We measure which calculators get used and which pages people arrive on, so we know what to improve. It is switched off until you press Allow on the cookie notice — decline, and Google receives no cookies from you and the site behaves identically. We do not run advertising, ad personalisation or any other third-party tracking, and IP addresses are anonymised.
Cookies. If you allow analytics, Google Analytics sets its own cookies to recognise a returning browser. We also store your consent choice itself in your browser’s local storage, so we do not have to ask on every visit — that one is not tracking and cannot identify you. Nothing else is stored. You can change your mind any time from the cookie settings link in the footer.
What analytics never sees. The vial sizes, doses and costs you type into a calculator are not analytics events and are never transmitted. That is true whether you allow analytics or not — the arithmetic runs entirely in your browser.
Server logs. Our hosting provider records standard request information such as IP address, timestamp, page requested and browser type. This is ordinary web server logging used for security and reliability, and it is not linked to anything you type into the calculator.
The Android app (Dose Tool)
Your log stays on your phone. The doses, vials, sites, notes and settings you enter in the app are saved in the app’s private storage on your device. They are never sent to us and we cannot see them. There is no account.
Android backup. If you have Android’s own backup switched on, Google includes the app’s data file in your device backup so it can be restored on a new phone. That backup is Google’s service, stored under your Google account; we have no access to it.
Subscriptions. Payments are handled by Google Play — we never see your card or bank details. To check whether a subscription is active, the app uses RevenueCat, Inc. as a service provider. RevenueCat receives a random app user ID created when the app is installed, your Google Play purchase records for this app (product, price, currency, dates, country) and basic technical data such as device model, OS version and IP address. It receives nothing from your log.
No analytics or advertising in the app. The app contains no analytics, advertising or tracking SDK. Links in the app open this website, tagged so we can count visits that came from the app; the website analytics described above then apply, and only if you allow them.
Deleting your data. In the app, Settings → Delete everything removes every dose and vial from your phone; uninstalling the app removes all of its data. Subscription records are kept by Google Play and RevenueCat as long as billing and tax rules require. To ask us to have the RevenueCat record for your purchases deleted, email us from the contact page with the Google Play order number (it starts with GPA.).
If you email us
Mail sent to our contact address is forwarded to a personal mailbox so we can reply. We keep that correspondence only as long as needed to deal with your message. We do not add you to any mailing list.
What we never do
We do not sell data. We do not share data with advertisers or data brokers. We do not build profiles of visitors. Because the calculator sends nothing to us in the first place, there is no dosing or health information here to sell, leak or hand over.
Your rights
If you are in the UK, EU or a jurisdiction with comparable law, you have rights to access, correct and erase personal data held about you, and to object to its processing. Since the only personal data we might hold is an email you chose to send us, most requests amount to asking us to delete that email, which we will do on request.
Changes
When this policy changes in a way that affects you — particularly if accounts, payments or analytics are added — the date at the top will change and the new terms will be described here rather than quietly swapped in.
Contact
Questions about privacy go to our contact page.