[oefrha]

I kid you not, I use Spotlight on macOS (cmd+space) as my simple calculator if I’m outside the terminal. If I’m inside the terminal I probably have an IPython instance open. For advanced stuff I use Mathematica as mentioned here: https://news.ycombinator.com/item?id=23428991

[perryprog]

Not to mention, Spotlight does a /bunch/ of unit conversions. You can even type things like `1km/h to kt` for example. There's quite a few units defined already that I'm usually pleasantly surprised. This also works on iOS.

The one downside is you can't do unit conversions of a mathematical expression, just of a number. (i.e., 2^2 m/s does not work but 4 m/s does).

Whenever I have to do something more complicated I usually use M-x calc or maxima with ezunits.