Privacy policy

1 · The short version

The calculators on this site are free and require no sign-in. Your project numbers never leave your browser — the math runs on your device and nothing you type into a calculator is transmitted to us or to anyone else.

We use Google Analytics to see which pages get visited and which calculators get used. That's the extent of it. We have no accounts, no newsletter, no payments, and we don't currently serve advertising.

2 · What we collect

Automatically, from everyone

• Pages you visit and how you arrived (referring site)
• Whether a calculator on the page was used — a single event, with no inputs attached
• Approximate location derived from your IP address, no more precise than region
• Device type, browser, and screen size

Only if you send it to us

• The name, email address, optional zip code and message you type into the contact form
• Attached automatically to that submission by our host: your IP address, browser and device string, and the page you submitted from

We don't ask for a phone number anywhere on this site, and we have no way to receive one.

That's the complete list.

3 · What we don't collect

Worth stating plainly, because many sites in this category do collect these:

• Your calculator inputs. Dimensions, materials, finishes, and totals stay on your device. They are not sent to a server, stored, or logged.
• Your name, phone number, or address, unless you type them into the contact form yourself.
• Payment information. We don't take payments.
• Account data. There are no accounts.

4 · Who we share it with

• Google Analytics 4 — traffic analytics. Sets first-party cookies. Google does not receive your full IP address, and we send it nothing that identifies you personally.
• Netlify — hosts the site and receives standard web-server request logs, plus any message you submit through the contact form.
• Google Fonts — serves the typefaces used on the site.

Nobody else. We have no advertising partners, no data brokers, and no contractor or lead-referral relationships at this time. If that changes, this policy will be updated before anything goes live, and the change will be described here rather than buried.

5 · Cookies & analytics

We use Google Analytics 4, which sets first-party cookies (_ga, _ga_*) to count visits and distinguish returning visitors from new ones. It records pages viewed, the site that referred you, approximate region derived from your IP, and your device and browser.

We set no advertising cookies and no third-party tracking cookies. You can opt out of Google Analytics on every site you visit using Google's browser opt-out add-on, or by using your browser's tracking protection.

6 · Your rights

Depending on where you live, you may have the right to see, correct, delete, or export the personal information a company holds about you.

In our case there is usually nothing to act on — we hold no accounts and no personal information about visitors who only use the calculators. If you have written to us through the contact form and want that message deleted, ask and we'll delete it. We aim to respond within 30 days.

7 · Retention

• Analytics: 14 months in Google Analytics, then automatically deleted
• Server logs: retained by our host on their standard schedule
• Contact form messages: kept while we're corresponding, then deleted on request — including the IP address and browser details attached to the submission

8 · Children

This site isn't directed at children and we don't knowingly collect information from anyone under 13.

9 · Changes

If we add anything that changes what we collect — advertising, a mailing list, or a contractor referral feature — this policy will be updated before that feature goes live, and the effective date above will change.

10 · Contact

Privacy questions or requests: use the contact form and select “Privacy / legal” as the topic.