Privacy
Plain English, because a policy nobody can read protects nobody. Last updated .
Who runs this site
Plain Reckoner is operated by Plain Reckoner, established in Curitiba, Paraná, Brazil (residence). We are the data controller. Postal address: Curitiba, Paraná, Brazil. Contact: contact@plainreckoner.com.
The short version
- The calculators run in your browser. You can use every one of them without giving us anything.
- We record the numbers you enter, without anything that points back to you, because knowing what people are trying to work out is how we decide what to build.
- We only email you if you asked twice — once in the form, once by clicking a link we send you.
- Advertising on this site is served by Google, which sets its own cookies. That is described below, and in the EEA and UK you are asked first.
- We have never sold data and the business does not have a version of itself where that makes sense.
What we collect, and why
When you use a calculator
The values you type, the tool you used, roughly how long you spent and whether you recalculated. There is no name, no email and no account attached. We keep it because it tells us which problems people actually have — the legal basis is our legitimate interest in knowing what to build next (GDPR Article 6(1)(f)), and it is the reason the tools are free.
When you subscribe
Your email address, the page you subscribed from, the exact wording you agreed to, and the date. We store the address as a one-way hash plus a copy held only until you confirm — so an unconfirmed signup disappears by itself after 48 hours. The legal basis is your consent (Article 6(1)(a)), and you can withdraw it at any time from the link in every email.
When your browser reaches our server
Your IP address and the page you asked for, in the server log. That is unavoidable — it is how the request arrives — and it is deleted after 14 days.
Advertising
This site carries advertising served by Google AdSense. Google may set cookies or read device identifiers to select ads and measure them, and Google is a separate controller for that processing — what it does is governed by Google's own policy.
If you are in the EEA, the UK or Switzerland you are asked for consent before any advertising or analytics cookie is set, and refusing is a single click that costs you nothing on this site. You can change your answer at any time from the link in the footer. Outside those regions you can opt out of personalised advertising at Google My Ad Center.
Who else receives data
| Who | What for | What they get | Status |
|---|---|---|---|
| Buttondown | Sends the email newsletter you asked for | Your email address, and the page you signed up from | Not yet in use |
| Google AdSense | Shows the advertising that pays for this site | Your IP address, device and browser, and advertising cookies where you allow them | Not yet in use |
| Google Privacy & messaging (CMP) | Asks for your consent before any advertising cookie is set | Your consent choice, stored in your own browser | Not yet in use |
| GoatCounter | Counts page views so we know which tools are used | Page URL, referrer, country, and a daily rotating hash — no cookie, no cross-site identifier | Not yet in use |
| DigitalOcean | Runs the server this page was served from | Whatever your browser sends to reach us, including your IP address | Not yet in use |
Rows marked not yet in use are listed in advance so this page is never behind the site. Nothing is sent to them until the status changes.
How long we keep things
| What | Stored as | Kept for |
|---|---|---|
| Unconfirmed signup | A hash of your address, plus the plaintext held only until you confirm | 48 hours, then deleted automatically |
| Confirmed subscriber | A hash of your address, with the date and wording of your consent | Until you unsubscribe |
| Calculator inputs | The numbers you entered, with no identifier that points back to you | 24 months |
| Server logs | IP address and request line | 14 days |
Your rights
This site is operated from Brazil, so the LGPD (Lei Geral de Proteção de Dados, Lei nº 13.709/2018) applies to everything described above. Under it you may confirm that we process your data, access it, correct it, ask us to delete it, ask what we share and with whom, request it in a portable form, and withdraw consent at any time. Brazil's supervisory authority is the ANPD, and you can complain to them about us.
If you are in the EEA or the UK, the GDPR gives you the same set of rights, and you may complain to your own national data protection authority. If you are in California, the CCPA gives you the rights to know, to delete, and to opt out of sale — we do not sell data, so there is nothing to opt out of.
Email contact@plainreckoner.com and we will answer within 30 days. One honest limitation: because subscriber addresses are stored as hashes, we find your record by your address — so a deletion request has to come with the address it concerns. You can also complain to your national data protection authority.
How long we keep a record of your consent
If you unsubscribe we stop emailing you immediately — not within some number of working days. We do keep the record that you once consented, and its date and wording, for about three years. That is not us relying on your consent after you withdrew it: it is a separate legal basis (GDPR Article 6(1)(c) and (f)), because if anyone ever asks whether we had permission to email you, the only way to answer is to have kept the proof. We are telling you now rather than in a footnote later.
Children
This site is not intended for children under 16, and we do not knowingly collect their data.
Changes
The date at the top changes whenever this page does. Anything that materially changes what we collect will be announced in the newsletter before it takes effect, not after.