Many of the calculations and conversions I need to do on a regular basis can be done by hand. I can do them with a pen and paper, or with a simple 4-function or scientific calculator. Sometimes they require a scratch pad and a calculator.
But just because I can do it by hand doesn’t mean that’s what I do.
For simple calculations I use my computer’s built-in calculator application. If I have a browser window open, I use Google. Google’s calculator and conversions are pretty convenient.
Google can handle more complex conversions, such as inch pounds of torque to Newton meters, but can sometimes get hung up on syntax.
Because of this I tend to use Wolfram Alpha more for anything but the simplest of conversions or calculations.
Wolfram Alpha is a computational knowledge engine that can spit out information as easily as it can handle unit conversions.
Wolfram Alpha can sometimes get confused too, but when it does it gives hints as to what’s wrong. A lot of the time it shows the work, so you can see how it arrives to an answer.
If you type in 100 in lbs in Newton meters, you won’t get the right answer, but you will if you type in 100 in-lbs in Newton meters. Wolfram Alpha also does not correctly interpret 100 in-lbs in nm or 100 in-lbs in NM, but it does provide the correct conversion and answer under their additional conversions section.
I do most of my inch-to-metric and metric-to-inch torque conversions through Wolfram Alpha, and inch-lbs to ft-lbs and ft-lbs to inch-lbs through Google.
When converting new units for the first time, I always do the conversion by hand using the proper conversion factors or steps. Then I use Google or Wolfram Alpha to ensure that my calculations and theirs add up. Sometimes I will also look up values in a conversion table or chart. This way I know that my input is being properly interpreted by Google or Wolfram Alpha, allowing me to trust their calculations and conversions in the future.
Wolfram Alpha can do so much more than simple calculations, but it’s not quite as good as it could be for workshop use.
What’s the diameter of a #8 machine screw? It gets this one on the first try.
Tap drill size for a 1/4″ bolt? This one took a few tries, and it gives the wrong answer – 0.209″ instead of 0.201″.
24 AWG wire size? It kind of gets this one right, but only if you leave out the “size” part from the input.
So it’s not quite perfect, but it does get better and better with time. Nevertheless, it’s a pretty decent tool for handling conversions and calculations.
Try It(Wolfram Alpha)
If you’re just looking to take a short break and have fun, hit the “random” button and see where it takes you. This is how I now know that the orbital period of Quaoar is “1.5 x as long as the approximate time you would have to lie on your back before a bird would poop in your mouth”.