Privacy policy

Last updated: September 2026

The short version

Calculations happen entirely in your browser. The values you type into a calculator are never sent to us and are never stored on a server. We do not ask you to create an account, and we do not sell data.

What is stored in your browser

Your theme, preferred currency, recent searches and saved calculators are kept in your browser’s local storage so the site remembers them on your next visit. They stay on your device, are not transmitted to us, and clearing your browser data removes them.

Analytics

We record anonymous usage counts — which pages are viewed, which calculators are used, and which searches return no results — so we can fix gaps and decide what to build next. This uses no cookies and no cross-site tracking.

To count repeat visits without identifying anyone, a one-way hash is derived from your IP address and browser user-agent together with a secret salt and the current date. The hash changes every day and cannot be reversed to recover your IP address. We store the hash, not the IP address. Your browser’s Do Not Track or Global Privacy Control setting is honoured — when either is on, no analytics request is sent at all.

Advertising

This site does not currently display advertising. If that changes, this policy will be updated to describe the advertising provider and the choices available to you before any ads appear.

Voluntary support payments

If you choose to support the site through Buy Me a Coffee, the payment is processed entirely on their platform under their own privacy policy. We receive a record of the supporter name, amount and date so we can acknowledge support; we never receive your card details, and we do not store the messages attached to a payment.

Server logs and security

Like any website, our hosting provider processes standard request data such as IP address and user-agent in order to deliver pages and to apply rate limits that protect the service from abuse. This data is used for operation and security only.

Children

The site is a general-purpose reference tool and is not directed at children under 13. We do not knowingly collect personal information from anyone.

Your choices

You can clear locally stored preferences at any time through your browser settings, and you can opt out of analytics by enabling Do Not Track or Global Privacy Control in your browser. Because we do not hold an account or a profile for you, there is no personal record for us to export or delete.

Changes and contact

If this policy changes, the date above will be updated. Questions are welcome — see the contact page.