Online Unit Conversions for The Common, The Complex, and The Unexpected


One website I used almost every day as a design engineer (and continue to use often) is  If you can think of an engineering or scientific application with unique units, this website will probably convert them.  It’s free to use and doesn’t require any registration.  The site claims “5,000 units and 50,000 conversions” and receives over half a million unique visitors a month based on has all the standard conversions you will need like Energy with 100 different units, Mass Flow Rate with 38, Force with 37, Acceleration, Density, Power, Pressure, Viscosity, etc.

The site also maintains many more obscure conversions and calculations like Radioactivity & Radioactive Decay, Sheet Metal & Wire Gauge, and even Sieve Density, as well as some less useful but generally interesting conversions like Astronomical Units, Weights on Other Planets, International Clothing Sizes, and other Fun Stuff.

For those engineers without the benefit of a a high end graphing calculator, the site even has an Algebraic Equation Solver.

If you can’t find a conversion that you need, the site has a forum where other engineers can help with your application.  The site admins scan this forum to discover new conversions to add to the main site.  There is even detailed information on how many of these conversions are calculated so you can see the math working behind the scenes.  This is great for students.

If you have a really complex application or problem, the site’s admins provide an email where you can contact them directly.  They claim to respond within a few days.

The site makes most calculations to seven decimal places (no one really remembers significant figures anyway) but suggests you double check everything for critical or safety related projects.

What other online resources do you use often at work?  Product Sourcing?  Engineering or Scientific Research?  Design References?  CAD Libraries?

Category: Online Resources

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One Response

  1. Ginger Terry says:

    http://www.onlineConversion.Com is an excellent resource and along with that I use wikipedia for unit definitions often for the unit names that are unfamiliar to me. I wish they had a section for all unit descriptions on the site itself so we didn’t have to go to other places to check for it. 2 other unit conversion sites that we use are and I often think that usability of these sites are a little better however all 3 of the sites still lack the conversion formulas for most units.


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