Privacy

What this site does with your data

Short version: our pages ask you for nothing, send us nothing and set no cookies. The details, including what other companies receive, are below.

Last updated: 11 November 2026

Who we are

This website is run by Spool & Margin, a small studio that makes pricing spreadsheets and calculators for people who sell 3D prints. For anything on this page, write to [email protected].

What our pages do not do

• No accounts, no sign-up, no contact or newsletter forms.
• No analytics, no advertising scripts, no tracking pixels, no social media plugins.
• Our pages set no cookies.
• The calculator does not send what you type to us or to anyone else. All of the arithmetic happens in your browser.

What the calculator saves in your browser

So that your numbers are still there on your next visit, the calculator saves the values in its input fields and the currency symbol you chose in your browser's local storage, under a single entry named spoolmargin.calc.v1.

• It stays on your device. We cannot read it, and it is not sent anywhere.
• It contains only the numbers you typed. It holds no name, no identifier and nothing about your device.
• It has no expiry date. The "Reset" button on the calculator deletes it, and so does clearing site data in your browser.
• If your browser blocks local storage, the calculator still works; it just starts from the example values each time.

This kind of storage exists only to provide a feature you are using, so we do not show a consent banner for it.

What other companies receive when you visit

Loading any web page means your browser contacts the computers that serve it. Those computers see your IP address and basic technical details such as your browser type. We do not receive or keep that data ourselves, but one company is involved:

• The host. The site is hosted on Cloudflare Pages, a service of Cloudflare, Inc. Cloudflare delivers the pages, processes technical data such as your IP address and browser type to deliver and protect them, and may keep standard server logs. We have not turned on any Cloudflare analytics or tracking feature, and our pages set no cookies. See Cloudflare's privacy policy.

If we move the site to a different host, we will update this page.

Links to Gumroad

Our spreadsheets are sold and delivered by Gumroad. Links from this site to Gumroad carry a short tag (for example utm_source=site) that tells us a visit came from this website and from which page. The tag contains nothing about you.

Once you are on Gumroad, Gumroad's privacy policy applies. Gumroad collects your payment and tax details. We never see your card or payment information.

If you buy or download a spreadsheet

Gumroad shares with us the email address you gave at checkout and the details of your order (what you bought, when, and the amount). We use them only to:

• answer your questions and handle refund requests;
• keep the business records the law requires;
• tell you about a new version of the product you bought. Such emails are sent through Gumroad, and each one has an unsubscribe link.

We do not sell this information, share it for advertising, or add it to any other list.

If you email us

We receive your email address and whatever you write, and we use them to reply. We keep the conversation for as long as it is needed to deal with your request and for our records, then delete it.

Your rights

You can ask us what information we hold about you, and ask us to correct it or delete it, by writing to [email protected]. We will answer within one month. We may need to keep records of a purchase where the law requires it.

If you are in the European Union or the United Kingdom, data protection law also gives you the right to object to or restrict our use of your data, to receive a copy of it, and to complain to the data protection authority where you live. Our reasons for using the data described above are to respond to your request, to support a product you obtained, and to meet legal record-keeping duties. We are based outside the EU and the UK, so information you send us is handled outside those regions.

For data held by Gumroad or Google, contact those companies directly; they decide how they use it.

Children

This site is made for people who run or plan a small business. It is not directed at children, and our pages do not collect personal information from anyone.

Changes to this page

If the site starts doing anything not described here, we will change this page first and update the date at the top.