Your numbers never leave your browser

What happens when you use a calculator

The arithmetic is JavaScript that your browser downloaded once and now runs locally. When you type a loan balance, a salary or a weight, that value stays in your device’s memory, is used to compute the answer on screen, and is gone when you close the tab.

There is no server to receive it. Plain Number is a set of static files — there is no database, no API and no backend that could store a calculation even if we wanted it to.

How that promise is enforced, not just stated

Every page is served with a Content Security Policy that names exactly which hosts anything on this page may talk to: our own domain, and the analytics described below. Nothing else. A request to any other destination is refused by your browser, whatever our code asks for.

The calculators themselves make no network requests at all, so the figures you type have nowhere to go. You do not have to take our word for it: open your browser’s developer tools, switch to the Network tab, and use any calculator. You will see the requests described below, and none of them carrying anything you entered.

No accounts, and what is measured

• No accounts. There is nothing to log in to and no profile of you anywhere. You can give us an email address for occasional updates if you want to — that is the only personal information this site ever asks for, it is entirely optional, and no calculator will ever require it.
• Analytics, and only page views. Google Analytics counts which pages are opened and roughly where in the world from, using a cookie to tell a returning visitor from a new one. It is set out in full below. No session recording, no heatmaps, no Meta pixel, no A/B testing tool, and nothing you type into a calculator.
• Advertising. Pages may carry a sponsorship — a static image and some words served from this domain, with no third-party script, cookie or pixel. None are sold at the moment, so no page currently carries one. The advertising disclosure explains how it is sold and what an advertiser does and does not get.
• No local storage. We do not write your inputs to local storage or session storage either — closing the tab really does discard them.

Analytics: counting visits, not people

This site uses Google Analytics to count page views. That is a real change from collecting nothing, and it deserves a plain statement rather than a clause.

What has not changed, and will not: the figures you type into a calculator are never transmitted anywhere. They are not sent to Google, to us, or to anyone else. The arithmetic runs entirely in your browser, and the analytics tag is never given a calculator input, a result, or anything you typed.

What Google receives when you open a page:

• The address of the page, the page you arrived from, and a timestamp.
• Your IP address, which Google uses to derive an approximate location — country, and usually region or city — and then discards. We never see the address itself.
• Your browser, operating system, device type and screen size.
• A randomly generated identifier stored in a cookie, so that four pages opened in one sitting count as one visit rather than four visitors. It identifies a browser, not a person, and it is set when the page loads.

We have switched off Google Signals, which means the advertising and cross-device features of Google Analytics are disabled for this site: your visit is not joined to a Google account, is not used to build an advertising audience, and cannot be used to retarget you elsewhere. We want a number on a chart, not an audience.

Why measure at all. Sponsorships are sold directly to advertisers, and an advertiser reasonably asks how many people would see a placement. Without a count there is no honest answer, and without that revenue there is no site. It is also how we learn which calculators are worth improving.

How to opt out. Blocking third-party scripts or cookies in your browser stops all of it, as does Google’s own opt-out browser add-on, and any of the common content blockers. Nothing on this site breaks if you do — every calculator works identically, because none of them ever needed the network. How Google handles data from sites using its services is described in its partner sites notice.

The one thing that is logged, by our host

Honesty requires naming this. The site is hosted by Netlify, and like every web server on the internet, Netlify’s servers process the technical details inherent in delivering a page to you: your IP address, the page requested, your browser’s user-agent string, and a timestamp. This is how the web works at the transport layer and happens before any of our code runs.

We do not use those logs to build a profile of you, and they contain none of the figures you enter into a calculator — those never reach the network. Netlify processes this data as our hosting provider under its own privacy notice.

Where our published figures come from

Some pages show numbers published by an authority — tax brackets, the Social Security wage base, exchange rates. Those are baked into the site when it is built, not fetched while you browse, so visiting a page that shows an exchange rate does not tell anyone that you looked at it. Each page links to the authority that published the figure and shows the date it was checked.

If you join the mailing list

The one place this site asks for anything is the signup at the foot of the page. It is optional and nothing depends on it.

• We store your email address, and nothing else. Not your name, not what you looked at, not what you calculated. There is no tracking pixel in the messages and we do not know whether you opened one.
• It is used for one thing. Telling you about new calculators, at most monthly. It is never sold, rented, shared, or used to advertise at you.
• Leaving is one click. Every message carries an unsubscribe link, and your address is deleted rather than suppressed. You can also just write to us and it is gone the same day.

The form is handled by Netlify, which receives the submission as our processor. It is an ordinary form post to this domain — no third-party script runs on the page to make it work, which is why the signup changes nothing else on this page.

Your rights

Laws such as the GDPR and the CCPA give you rights to access, correct, port and delete the personal data a company holds about you. Unless you have joined the mailing list we hold nothing that identifies you, so there is nothing for us to return or erase. If you have, the only record is your email address, and you can have it back or have it deleted by asking.

The analytics described above are reported to us only as totals — page views, countries, browsers. We cannot look up an individual visitor, and we have no way to connect a visit to a mailing-list address or to anything you typed. If you would like your analytics data excluded entirely, the opt-outs above do it at source, before anything is sent.

We do not sell personal information. Some privacy laws define “sharing” broadly enough to cover identifiers set by a third party on our pages; where that applies, the controls linked above are how you turn it off.

If you would like to ask about any of this, write to hello@plainnumber.com.

Children

We do not knowingly collect personal information from children. Nothing on this site asks a visitor’s age, name or identity, no calculator requires an account, and the figures anyone types are never transmitted — which is as true for a child as for anyone else.

Changes to this notice

If the site ever gains a feature that changes any of the above, this page is updated in the same commit that ships it, and the date at the top changes. A version of this page that claims less than the site actually does would be the only real failure mode here, so it is the thing we watch for.

Who operates this site

Plain Number is operated by Media Yard LLC. See the Terms for the rest of the legal relationship, and the AI disclosure for how the site was built.