Short version: what you type into a calculator stays in your browser and is never sent to us. We keep no accounts and collect no personal information directly. Advertising and analytics partners do set cookies, and this page explains what they do and how to control them.
Calculator inputs
All calculations execute locally in your browser using JavaScript. The values you enter are not transmitted to our servers, not logged, and not stored anywhere but on your own device. If you use the Copy link button, your inputs are encoded into the URL you copy — that URL is created in your browser, and it is shared only if you choose to share it.
Local storage
To make return visits convenient, a calculator saves your most recent
inputs and your light/dark theme preference in your browser's localStorage. This data never
leaves your device and is not readable by us. Clearing your browser's site data removes it, and the
Reset button on any calculator clears that calculator's saved values.
Contact form
The contact form is the only place this site asks you for anything. What you type into it — your name, your email address, and your message — is stored in a database on this site's own server so it can be read and answered. It is not sent to a third party, not used for marketing, and not added to any mailing list. Ask us to delete a message and we will.
Two things are recorded alongside it for abuse control. The first is a one-way keyed hash of your IP address, which lets us rate-limit floods without ever storing the address itself — the hash cannot be turned back into an IP, and it cannot be matched against anyone else's records. The second is your browser's user-agent string.
The form sets one small cookie, and only when you load the page it is on. It holds a signed token for the anti-spam picture and nothing else: no identifier, no tracking value, and nothing that survives the hour. It is strictly necessary for the form to work, it is not used for advertising, and the picture is generated by this site — no CAPTCHA service is involved and no third party sees you.
Server logs
Our hosting provider records standard web-server request data — IP address, timestamp, requested URL, referring page, and user-agent string — for security, abuse prevention and aggregate traffic measurement. These logs are retained for a limited period and are not used to build profiles of individuals.
Advertising
This site displays advertising supplied by third-party ad networks, including Google. These partners may use cookies, device identifiers, and similar technologies to serve and measure advertising, and in some configurations to personalise it based on your prior browsing.
Google's use of advertising cookies is described in How Google uses information from sites that use its services. You can opt out of personalised Google advertising at Google Ads Settings, and manage many other networks at optout.aboutads.info and Your Online Choices.
Where required by law — including in the European Economic Area, the United Kingdom and Switzerland — a Google-certified consent management platform asks for your choice before any non-essential cookie is set, and records it under the IAB Transparency and Consent Framework. You can change or withdraw that choice at any time from the privacy link the consent notice leaves on the page. If you decline, advertising is still shown but is not personalised.
Analytics
We do not run a third-party analytics product, and no analytics cookie is set by this site. What we know about traffic comes from the aggregate reports our host and our advertising partner produce from data they already hold; neither identifies individual visitors to us.
Your rights
Depending on where you live, you may have the right to access, correct, or delete personal data held about you, to object to processing, or to opt out of the sale or sharing of personal information. Because we do not maintain accounts or collect personal data directly, in most cases we hold nothing about you beyond transient server logs. To exercise a right or ask a question, use our contact page.
Children
This site is intended for a general audience and is not directed to children under 13. We do not knowingly collect personal information from children.
Changes
We will update this page when our practices change, and the date at the top of this page will change with it. Continued use of 4Calculators after a change constitutes acceptance of the revised policy.