About PhDino Calc 95
Maintained by Andrea Coppola · Last reviewed 21 September 2026
PhDino Calc 95 is a free set of 97 engineering calculators across 12 fields, presented as a retro Windows 95 desktop. Each calculator computes as you type, draws a live diagram of what it is calculating, and comes with a written explanation of the formula, its assumptions and where it stops applying. 11 project guides chain calculators together for real jobs such as sizing a deck footing or a home backup generator.
Who is behind it
PhDino is built and maintained by Andrea Coppola, an independent developer based in Italy. It is a personal project: there is no company, sponsor or editorial team behind it. Andrea holds a degree in Mechatronic Engineering from the University of Padua and has spent nearly three years designing electrical and industrial-automation systems for the oil and gas and chemical industries.
Why it exists
The aim is a collection of calculators that are quick to use, show their working, and explain what the numbers mean and where they stop being reliable, for students, makers and people planning a build. The Windows 95 styling is a design choice that keeps a large collection of small tools on one screen and easy to browse.
How the content is written and checked
The guides and the code were written with the help of an AI assistant (Claude, from Anthropic) working under the maintainer's direction. Nothing is copied from a textbook or another site: the formulas are standard published relationships, and the explanations are written fresh.
Because AI-written text can contain mistakes, the numbers do not rest on that text. Every calculator is tested automatically against expected answers worked out a different way, and the site cannot be published if a test fails. The Methodology page explains the method in full, lists what the tests do and do not prove, and keeps a public log of the errors found and corrected.
What PhDino is not
PhDino is an educational and screening tool. It is not a substitute for a licensed engineer, for the official text of a building code or standard, or, for the biomedical calculators, for clinical judgement: those are for learning and must not be used to make decisions about patient care. Several calculators are deliberate simplifications and say so at the top of their page.
How the site is funded
The calculators are free and need no account. The site is meant to be supported by advertising and by book links that earn a small commission. The book links are described on the Affiliate disclosure page and are chosen on merit. Advertising is never placed inside a calculator.
Get in touch
Found a wrong number, an unclear explanation, or a calculator you would like to see? The Contact page is the way to reach the maintainer, and reports of errors are the most useful messages of all.