Privacy policy

The short version

• Your inputs stay on your device Every calculation runs in your browser using JavaScript that is already on the page. Your dates are never sent to a server, because no server is involved in the calculation.
• No account, no email, no profile There is nothing to sign up for, nothing to log in to and nothing to unsubscribe from.
• No advertising cookies at the time of writing The site sets no cookies of its own and loads no third-party scripts. If that changes, this page changes first.
• No uploads You are never asked for a photograph, a scan, a document or a payment detail. Nothing you type is transmitted.
• You can verify most of this Open your browser's developer tools and watch the network tab while you calculate. The only requests should be for the page itself.

How the calculations work

Baby Tools is a set of static pages. Each page contains its own text, its own styles and its own small script. When you enter a last period date and a cycle length, the arithmetic happens in that tab: the script reads the two values, subtracts and adds days, and writes the result into the page. No request leaves your browser with those values attached.

Because of that design, we cannot see your due date, your cycle length, your conception date or the result card you download. We have no database of users, no analytics about which dates were entered and no way to reconstruct a visit from the numbers you typed. If you reload the page, the values you see are whatever your browser and the page itself decide to keep — not something fetched back from us.

The downloaded result card is drawn by your own browser onto a canvas and saved directly to your device. It is not uploaded, scanned or stored anywhere else. What you do with that image afterwards — sending it to a partner, printing it, posting it — is outside our control and outside this policy.

One honest caveat: a calculator running locally still produces ordinary web traffic when the page loads. Our hosting provider may record standard server information such as the requested file, the time, an approximate location derived from the IP address and the browser's user-agent string. That is a property of serving any web page, it is not used by us to identify you, and we do not link it to anything you typed.

Storage on your device (localStorage)

As of the effective date, none of our calculators writes anything to localStorage, cookies or IndexedDB. Your inputs exist only in the form fields of the page you have open.

Your browser may still restore a date you typed if you reload the page or return to the tab later, because browsers keep form values for their own convenience. That behaviour belongs to your browser, not to us, and the restored value never leaves your device.

If we later add a "remember my last date" option, it would be built with localStorage on your device only, so the calculator could pre-fill the field on your next visit. Even then it would not be transmitted, and this page would be updated before the feature shipped. To clear anything stored this way, open your browser's settings, find the section for cookies and site data, locate this site's address, and remove its stored data. Using a private or incognito window also clears it when you close the window. Clearing storage only removes the convenience of a pre-filled field; it does not affect your ability to calculate anything.

Cookies and analytics

Current position. Baby Tools sets no cookies. We run no analytics, no session recording, no heatmaps and no advertising. There are no embedded videos, social media widgets, comment systems, remote fonts or third-party scripts, so no outside company receives your visit through our pages.

What could change. This is a free site, and we may later want to know which pages are useful and, eventually, to cover hosting costs with advertising. If we enable something like Vercel Analytics for aggregate page views, or Google AdSense for advertising, those services would set cookies or similar identifiers and could collect information such as your IP address, approximate location, browser type and the pages you viewed. We would update this page first, name the provider, describe what it collects and explain how to opt out or refuse consent where the law requires a choice.

We are not promising that the site will stay cookie-free forever. We are promising not to add tracking quietly and then mention it in a footnote. If you want certainty about the current state, the effective date at the top of this page tells you when it was last checked.

Links to other websites

Our pages link to outside organisations so you can read the guidance we work from: the NHS, ACOG, the WHO and the CDC, among others. Those links are text links. Nothing from those sites loads on our pages, so they do not see you until you click.

Once you follow a link, you are on someone else's site and their privacy policy applies, not this one. They may set their own cookies, run their own analytics and ask you to accept their own terms. We do not control that, cannot see what they collect, and are not responsible for it. It is worth checking the privacy page of any health site you use, especially where a login or a symptom checker is involved.

Children's privacy

Baby Tools is written for adults — parents, parents-to-be and anyone helping them. It is not directed at children, and there is nothing on the site designed to appeal to them.

We do not knowingly collect personal information from anyone, including children under 13, and the local-only design means there is no mechanism for a visitor to submit information to us through the calculators. If a child uses the site, the same rule applies as for any other visitor: their inputs stay in the browser on that device. If you believe a child's information has reached us some other way, tell us through the contact route below and we will look into it.

Your choices

• Clear local data. Remove this site's cookies and site data in your browser settings, or browse in a private window.
• Block scripts entirely. With JavaScript disabled, the calculators will not run, but nothing else on the page changes — the explanations and sources remain readable.
• Use your browser's tracking protections. They have nothing to block here today, but they will apply automatically if that ever changes.
• Ask us. If you want to know whether a specific number could have reached us, the answer is almost certainly no, and we will explain why rather than just assert it.

There is no marketing list to leave, no account to delete and no profile to download, because none of those exist.

Changes to this policy

When this policy changes, the effective date at the top of the page changes with it. Material changes — a new analytics provider, advertising, a contact form that sends data anywhere — will be described in plain language rather than hidden in a revised paragraph, and will be listed in the update log below so the history stays visible.

We do not backdate policies, and we do not quietly widen what we collect while leaving the old date in place.

Update log

• November 10, 2026 — First version published. No cookies, no analytics, no advertising, no server-side processing of calculator inputs.

Contact

For corrections and privacy questions: use the contact link once the site launches. We have not published a dedicated privacy address yet, and we would rather say so than invent an inbox that nobody reads.

If your question is about the medical content rather than your data, the editorial policy explains how sources are chosen and how errors are corrected. For a plain description of who makes this site, see about Baby Tools.