Privacy Policy

Effective date: 1 September 2026

Short version: what you type into a calculator stays on your device unless you deliberately save it to an account, and we collect as close to nothing as a website can.

1. Calculator data — never collected

Every calculator on ListCalc runs entirely in your web browser using JavaScript. The numbers you enter — income, weight, loan amounts, measurements — are processed on your device and are not transmitted to, stored by, or visible to us in any form. Downloads (CSV, PDF, images) are generated locally in your browser. The "Copy link" feature encodes your inputs in a URL only when you press it, and only you decide who receives that link.

2. Information collected automatically

Our hosting provider, Cloudflare, processes standard technical data needed to deliver any website — such as IP address, browser type, and requested pages — for security (e.g. blocking attacks) and performance. This data is handled under Cloudflare's privacy policy. We do not use it to identify or profile you.

3. Cookies and local storage

If you browse ListCalc without signing in, we set no cookies at all. Cloudflare, our host, may set short-lived security cookies to protect the site from attacks.

If you create an account and sign in, two cookies are set so the site can remember you: lcu, an HttpOnly session token that keeps you signed in, and lcin, a simple yes/no flag that lets the page show your account menu. Both are marked Secure, last up to 90 days, and are cleared when you sign out. Neither is used for advertising or for tracking you anywhere else. Site administrators signing into the management panel receive a separate cookie scoped to the admin path, which ordinary visitors never receive. The full table is in the cookie policy.

The calculators also save data on your device using your browser's local storage (keys beginning "lc:"). This holds the inputs you last entered, any calculations you chose to save, your recent history and your light or dark theme preference. It stays on your device unless you turn on cloud sync (see section 7) — otherwise we have no way to read it. To clear it, press Reset on any calculator, or clear site data in your browser settings.

In the future we intend to fund the site with advertising (such as Google AdSense). If and when ads launch: advertising partners may use cookies or similar technologies to serve and measure ads, including personalised ads where permitted. Visitors in the EEA, UK and Switzerland will be shown a consent dialog first, and can choose non-personalised ads. Google's use of advertising cookies is described at policies.google.com/technologies/ads, and you can opt out of personalised advertising at Ads Settings. This policy will be updated on the day advertising goes live.

4. Analytics

We use Cloudflare Web Analytics to see aggregate traffic — page views, referring sites, country and browser — so we know which calculators are worth improving. It is cookieless: it stores nothing on your device, does not fingerprint you, and does not track you across other websites. It never receives anything you type into a calculator.

We run no other third-party analytics. If that changes, this policy will be updated first.

5. Contact form

If you use our contact form, we receive what you choose to send — your name, email address and message — and use it solely to reply to you. Messages are stored securely, are not shared with third parties, and are deleted once the conversation is resolved.

6. Accounts

An account is optional — every calculator works fully without one. If you create one, we store your email address, a salted hash of your password (never the password itself), the date you signed up, whether your email is verified, and which plan you are on. If you sign in with Google instead, Google provides your email address and basic profile details; we never see your Google password. We also keep a record of your active sign-in sessions so you can review and revoke them, plus a limited log of sign-in events for security. You can delete your account at any time from your account page, which removes your profile and everything saved to it.

7. Saved calculations and cloud sync

Saving a calculation keeps it in your browser. If you have ListCalc Premium and turn on cloud sync, the calculations you have chosen to save are also stored on our servers so they appear on your other devices. This is the one case where numbers you entered leave your device, and it only ever applies to items you explicitly saved — never to what you type as you type it. Synced data is tied to your account, is never sold or shared, and is deleted when you delete the item or your account.

8. Premium and payments

If you subscribe to ListCalc Premium, payment is handled by an external payment provider acting as merchant of record. We never see or store your card details. We receive only what is needed to give you access: your subscription status, plan and renewal date. If you join a waiting list for a feature that has not launched yet, we keep your email address for that purpose alone and delete it once the list has served its purpose.

9. Embedding ListCalc

Our calculators can be embedded on other websites. When an embed loads, we record the domain it was loaded on together with standard request data, so we can see where embeds are used and block abuse. This identifies the host site, not the individual visitor, and never includes anything typed into the calculator.

10. Children

ListCalc is a general-audience reference site and does not knowingly collect personal information from anyone, including children under 13.

11. Your rights

Depending on where you live (e.g. GDPR in the EU/UK, CCPA in California), you may have rights to access, correct, export or delete personal data. If you have never created an account we hold essentially nothing about you beyond any contact-form message you sent. If you do have an account, you can review and delete your data yourself from your account page, or email us and we'll act promptly.

12. Changes to this policy

We'll post any changes on this page and update the effective date above. Material changes (like the launch of advertising) will be clearly noted.

13. Contact

Questions about this policy: contact form or hello@listcalc.com.