Privacy & Cookies

The short version

PE-Calc hosts free engineering calculators that run entirely in your browser. The numbers you type into a calculator and the results it gives never leave your device. There is no account and no login. The site collects anonymous page-view statistics, stores newsletter email addresses for people who subscribe, and will show Google ads once the AdSense account is approved. Each of these is described below.

Calculator inputs

Every calculation runs in JavaScript on your own device. Inputs and results are not sent to any server, logged or stored. Printing or saving a page as a PDF happens entirely in your browser.

Page-view statistics

PE-Calc runs its own small analytics service rather than Google Analytics. When a page loads, the browser sends one record to that service (hosted at hc-refactored.fly.dev, operated by the same author). The record contains:

the page path and the referring page, if your browser sends one;
your screen size and your browser’s user-agent string;
any utm_ campaign tags in the link you followed;
a visitor identifier made by one-way hashing your IP address and user-agent with a secret salt.

Your IP address itself is not stored, and the hash cannot be reversed to recover it. Two events are also counted: printing a page, and submitting the newsletter form. The newsletter event records which form was used, never the email address. No cookies or device storage are used for any of this. The data is used only to see which pages are useful and where visitors come from. It is not sold or shared.

Requests from known search-engine and AI crawlers are logged on the server so the site can see how it is indexed. Requests from people are not affected by that log.

If you subscribe to The Hydraulic Notebook, or enter your email to download the reference-card PDF (which also subscribes you), your email address is stored so the newsletter can be sent to you. The form records which page and which signup box you used. The signup form is handled by the site host, Netlify, and the newsletter is sent through the email service Resend. Every issue has an unsubscribe link, and unsubscribing stops all mail. Your address is not sold, shared or used for anything else.

Advertising

The site loads Google AdSense so that it can show ads once the account is approved. Google and its third-party vendors use cookies to serve ads based on your prior visits to this and other websites.

Opt out of personalized advertising at Google Ads Settings.
Opt out of other vendors’ cookies for personalized advertising at aboutads.info or youronlinechoices.com.
See how Google uses information from sites that use its services.

Cookies and device storage

The calculators and cheat sheets set no cookies and write nothing to your device. Cookies on this site come only from Google AdSense. One interactive page, the Eclipse Predictor, saves your list of compared locations in your browser’s local storage so it is there when you return. That list stays on your device.

Third-party resources

Some pages load the KaTeX math library from the jsDelivr CDN to render equations. As with any web request, the CDN receives your IP address when it serves the file.

Children

PE-Calc is a professional reference and is not directed at children under 13.

Disclaimer

The calculators on this site are provided as-is for reference. Engineering calculations used in design or construction should be independently verified by a licensed Professional Engineer. PE-Calc is not a substitute for engineering judgment.

Contact

Questions about this policy, corrections and tool requests: see the contact page.