dog with book

Call be crazy but anytime I have to do the same calculation twice I start thinking about how to automate the process. The result is that I make a bunch of excel calculators & technical cheat sheets. You are invited to download these documents and use them as you wish, everything here is free and always will be!  –Enjoy!

Last Updated: November 2016

 Bolt Sizing Calculator (EXCEL) Calculate the strength of any size fastener.
 Heat Sink Quick Reference (PDF) Quickly design a custom heatsink.
 Strength of Materials Calculator (EXCEL) Calculate the strength of simple beams.
 Clevis Sizing Calculator (EXCEL) Calculate clevis strength and hole tearout forces.
 Wire Gauge Sizing Calculator (EXCEL) Calculate the ampacity of electrical wire.
 Shaft Key Sizing (EXCEL) Calculate the torque rating of shafts and keys.
 Air Cylinder Force Calcs (EXCEL) Calculate the force from pressure cylinders.
Ball Screw Calculator (EXCEL)  Determine the buckling load and critical speed of ball screws and lead screws.
Electric Motorcycle Calculator (EXCEL)  Estimate the performance of an electric motorcycle design prior to building one.
Engineering Economics Calculator (EXCEL)  Engineering economics class in an nutshell
Investment Portfolio Performance Tester (EXCEL)  Intended as a pseudo-realistic illustration of how an investment portfolio might perform over time.
 Financial Survival Pocket Guide (PDF)  Provides a succinct yet solid baseline for money management and investing skills.
 Simple BOM for Hobby Grade Use  (EXCEL)  Provides a starting point for a DIY grade bill of materials. Example provided is the TestrBot project.
3D Printed Part Cost Calculator (EXCEL) Calculate the cost per assembly of kits containing 3d printed and non-printed components


*This list is a perpetual work in progress. Check back every once in a while to see whats new! (I also take requests)

**The calculator excel documents are protected for quality purposes, use the TAB button to cycle through the unlocked cells.

***I cannot claim responsibility for any unintended consequences caused by the use or misuse of these resources.


  1. Great, except units of recommended tightening & ultimate breaking torque in the Bolt sizing calculator should be lb-in not in-lb.

    You have it expressed as an energy (scalar) where it should be expressed as torque (vector)


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