About PartCalc

Who built this

I'm a mechanical engineer with a B.S. from UC Berkeley, two years of industry experience, and a year of automotive engineering work. I built PartCalc because I kept running the same handful of calculations on the job — bending stress, bolt preload, factor of safety, section properties — and wanted a faster, more transparent way to do it with real McMaster-Carr parts instead of generic textbook numbers.

Most engineering calculators online either give you a black-box answer or make you look up every input yourself. PartCalc pulls material and geometry data directly from the McMaster product page and labels every value — SCRAPED, INFERRED, ESTIMATED, or COMPUTED — so you always know what you're signing off on.

Who this is for

PartCalc is built for two kinds of people:

• — Engineering undergrads who need to run real calculations for a project or internship and want a fast sanity check that shows the work, not just the answer.
• — New engineers (0–3 years) who learned these formulas in statics and materials science but need a reliable reference when the textbook is three offices away and the deliverable is due by EOD.

This is not a site for senior engineers who already have their FEA licenses and internal tools. It's for the person who just got handed a part number and needs to back up a hand calc quickly and correctly.

What you'll actually learn here

The blog covers the calculations that come up every day in real engineering work — not everything in your textbook, just what actually matters:

• Bending stress and when it governs failure
• Factor of safety — how to choose, not just what it means
• Bolt preload, torque coefficients, and joint design
• Section properties for the cross-sections you'll actually specify
• Stress transformation and when combined loading changes your answer

The material your intro statics and materials science classes covered, applied to the problems your boss will actually ask you to solve.

A note on accuracy

Every value PartCalc produces is labeled by source. Values scraped directly from McMaster are marked accordingly. When data is missing, PartCalc uses conservative gap-fill defaults from ASTM, ASME, and SAE standards — and tells you so. Nothing is hidden.

That said: PartCalc is a reference tool, not a substitute for engineering judgment. For safety-critical applications, verify all outputs against primary sources and have your work reviewed by a licensed engineer.

Get in touch

Questions, feedback, or a calculation type you wish PartCalc supported — send me a note at [email protected] .