Privacy policy

This policy explains what happens to information when you use Numerith. It describes how the site is actually built: if the way the site works changes, this page will be updated.

The short version

• Every calculation runs in your browser. The numbers and text you type into calculators are not sent to Numerith’s servers or to anyone else.
• You do not need an account. We do not ask for your name, email address or any other personal details to use the calculators.
• The site counts page views in an anonymous, cookie-free way (see “Anonymous statistics”). It honours Do Not Track and Global Privacy Control.
• Optional features (favourites, collections, history and display settings) are stored only in your browser and can be deleted at any time.
• If you choose to send a message or a calculator suggestion, what you write is stored on the site’s server so the operator can read it.
• Advertising may be switched on by the site operator; if it is, a consent prompt appears before any ad technology loads (see “Advertising”).

Calculator inputs

Calculator logic is downloaded to your browser with the page and runs there. Your inputs are not transmitted, logged, stored on a server or included in any statistics or advertising request. Results are produced locally as you type.

Share links contain only the page address by default. For calculators that do not involve personal financial, salary, tax or health information, you can choose to include your inputs in the link. They are placed after the “#” sign, a part of the address that browsers do not send to web servers — but anyone you give the link to can read them.

Anonymous statistics

To learn which calculators are useful, the site counts page views. For each view it records only the page path (for example /calculators/bmi-calculator), the interface language you selected, a device class (phone, tablet or computer, from the window width) and, for the first page of a visit, the website that linked to us. These are added to daily totals.

It does not set cookies, store your IP address or browser details, record calculator inputs or search text, or build a profile of you. To estimate the number of distinct visitors per day, a one-way hash of your IP address and browser details, mixed with a random value that changes every day, is held in the server’s memory only and discarded at the end of the day; it is never written to disk. Nothing is sent when your browser signals Do Not Track or Global Privacy Control.

Information stored in your browser

Numerith uses your browser’s local storage, not cookies, for the following, all under keys beginning with “numerith.”:

• Preferences — theme, contrast, language, digit style, preferred currency and your advertising-consent choice.
• Favourites and collections — the calculators you starred or grouped.
• History (off by default) — if you turn it on, which calculators you used and when. Inputs are remembered only if you separately allow it, and never for financial, property, salary/tax or health calculators.

This data never leaves your device and is not secure storage — anyone with access to your browser profile could read it. You can delete all of it at once on the privacy settings page or by clearing site data in your browser.

Offline support

The site registers a service worker that caches the site’s own files (pages, scripts, styles and the public calculator index) so that pages you have visited work offline. It does not cache anything you type.

Server and hosting logs

Like any website, the servers that deliver Numerith’s pages receive standard technical information with each request — such as your IP address, browser type, the page requested and the time. Numerith’s application code does not copy this into its statistics. Such logs are kept by the hosting provider for security and reliability according to its own retention policy; the operator of this site should name the hosting provider here once deployed.

Advertising

If the site operator enables advertising, the site uses Google AdSense. Google and its partners may use cookies or similar technologies to serve and measure ads and, if you consent, to personalise them based on your visits to this and other sites. Ad scripts are loaded only after you make a choice in the consent prompt, and if you decline, only non-personalised ads are requested.

Ad requests never include your calculator inputs. You can change your choice at any time on the privacy settings page. Learn how Google uses information at policies.google.com/technologies/partner-sites and manage ad personalisation at adssettings.google.com.

Contact form and suggestions

When you send a message or a calculator suggestion, the text you type (and your name and email address, if you choose to give them) is sent to the site’s server and stored there so the operator can read and answer it. Your IP address and browser details are not stored with it, and it is not shared with advertisers. To limit spam, the server briefly counts recent submissions per address in memory. You can ask for a message of yours to be deleted by writing to the contact address.

Children

The site is not directed at children and does not knowingly collect personal information from them. The calculators collect no personal information at all.

Your rights

The calculators and anonymous statistics hold no personal data about you on our servers, so there is normally nothing to access, correct or delete. For a message or suggestion you sent, you can ask the operator to show you or delete it. Data in your browser is under your control. If advertising is enabled, Google acts as an independent controller for its advertising data; see the links above.

Contact

Contact details will be published on the contact page once the site operator has configured them.