Privacy Policy
Last updated: 3 August 2026
This policy explains what information batchcalculator.com (the “Site”) collects, who processes it on our behalf, and what choices you have. It covers the Site only, not the third-party shops that sell our printables, which have their own policies.
1. The short version
The calculators collect nothing. Everything you type into a tool stays in your browser. The only personal data we ever hold is what you deliberately type into a form: your email address, and whatever you write in a message.
2. What we collect
Calculator inputs, nothing
Every calculator on this Site runs entirely in your browser. Weights, ratios, oil blends, prices, batch sizes: none of it is transmitted to us, stored, or logged. We could not tell you what anyone has ever calculated, because we have never had it.
Free PDF and printable downloads
Some pages offer a printable, a cheat sheet, a checklist, a worksheet, in exchange for an email address. If you choose to use one of those forms, we collect:
- the name you enter
- your email address
- which download you asked for, and which page you asked from
- the date and time
This is an opt-in. The form is never a condition of using a calculator, and the tool on the page works whether you fill it in or not. Ticking the consent box is how you agree to hearing from us about that craft; the download itself starts either way.
We use your address for two things: sending you the file you asked for, and, if you ticked the box, occasional emails about new calculators and printables for the craft you signed up under. That is the whole list. We do not email you about other crafts unless you signed up for those too.
Every email carries a one-click unsubscribe link. Unsubscribing removes you from the active list immediately and needs no explanation or reply.
If we ever want to use your address for something materially different from that, we will ask you first rather than assume the original tick covers it.
We will never sell or rent your email address, and we do not use it for advertising or share it with advertisers.
Contact form
If you use the contact form we receive your name, your email address, the topic you selected and your message. We use it to answer you, and for nothing else.
Analytics
We use Google Analytics 4 to understand which tools people find useful. It records pages visited, time on page, approximate location at country or region level, device type, browser, and the site or search that sent you.
Google Analytics sets cookies in your browser (_ga and _ga_*) that hold a randomly generated identifier. That identifier lets us count you as the same visitor across pages and sessions. We never combine it with your name or email address, we do not use it to identify you personally, and we do not build advertising profiles or share it with advertisers.
You can opt out at any time by installing Google’s own browser add-on, by blocking cookies for this Site, or by using your browser’s tracking protection. None of that affects any calculator here, they all run entirely in your browser.
3. Who processes your data
These are the third parties that handle Site data on our behalf. Each is bound by its own agreement and privacy policy.
| Processor | What it handles | Policy |
|---|---|---|
| Supabase | Stores email-capture entries (name, email, download, page, timestamp) and a copy of contact-form messages | supabase.com/privacy |
| Web3Forms | Delivers contact-form messages to our inbox | web3forms.com/privacy |
| Cloudflare | Hosts and serves the Site; processes request logs for security and delivery | cloudflare.com/privacypolicy |
| Google Analytics 4 | Usage statistics, pages, sessions, device, referrer, country-level location | policies.google.com/privacy |
Supabase stores data on infrastructure that may be located outside your country. Where that involves a transfer out of the UK or EEA, it is made under the transfer safeguards in Supabase’s own data processing agreement.
Amazon and other retailers we link to are not our processors. See section 5.
4. Cookies
The calculators need no cookies and set none. They run entirely in your browser and nothing you type into one is sent anywhere.
The only cookies this Site sets are Google Analytics’ _ga and _ga_*, which hold a random visitor identifier so we can count visits. They are set when a page loads.
You can refuse them with Google’s opt-out add-on, by blocking cookies for this Site in your browser, or with any tracking-protection feature your browser offers. Blocking or deleting them does not affect any calculator here.
5. Affiliate links
Some pages link to products at third-party retailers, marked as affiliate or sponsored links. Clicking one may set a cookie on that retailer’s site, which they use to attribute a purchase to us. That happens under the retailer’s privacy policy, not ours. We receive commission reports only, never your name, your address, or what you bought.
See the affiliate disclosure for how those links are marked.
6. How long we keep things
| Data | Kept for |
|---|---|
| Calculator inputs | Not collected |
| Email-capture entries | Until you unsubscribe or ask us to delete them |
| Contact messages | As long as needed to deal with the enquiry, then deleted |
| Analytics | Per the retention period set on our Google Analytics property |
7. Your rights
Depending on where you live, including under the UK GDPR and EU GDPR, you may have the right to:
- access the personal data we hold about you
- correct it if it is wrong
- delete it (“right to be forgotten”)
- object to or restrict how we use it
- receive a copy of it in a portable format
- withdraw consent at any time, which for the mailing list is the unsubscribe link in any email, or contact us and we will delete your address outright
To exercise any of these, contact us and say which right you are exercising. We will respond within one month. You also have the right to complain to your data protection authority, in the UK, the Information Commissioner’s Office at ico.org.uk.
Our lawful basis is consent for the mailing list, and legitimate interests for answering the messages you send us and for keeping the Site working and secure.
8. Children
This Site is not directed at children under 13, and we do not knowingly collect personal information from them. If you believe a child has submitted personal information, contact us and we will delete it.
9. Security
Email addresses and messages are held in Supabase behind row-level security policies that permit inserts only from the Site, the Site’s public key cannot read the table back. The Site is served over HTTPS.
No system is perfect. If you believe there has been a security issue with this Site, please tell us.
10. Changes
We may update this policy. Material changes will be reflected in the “Last updated” date at the top of this page.
11. Contact
Questions about this policy, or a request about your data, get in touch.