I also tend to just use a CAS, specifically maxima (either commandline, via emacs, via wxMaxima or via notebook, see https://github.com/robert-dodier/maxima-jupyter ). It has the plotting, great units etc, and also incredibly handy to do things like a taylor expansion around a point with no effort.
If not maxima, then the old M-x calc will usually do the job
It might be a bit late to ask, but out of curiosity, what kind of tools are you using nowadays to replace calculators? I prefer free and open source ones, so I have a shortcut to open a terminal with GNU Octave (or python if not installed).
I use xcas when I need CAS, but the interface is a bit unwieldy.
To be frank, I do the same with the GNU Octave CLI, which is IMO much more suited to evaluating mathematical expressions, and very short programs. Out-of the box, that is.
The right answer is probably to use the right tool for the job, be it xcas, octave or python. Microsoft's calculator is probably better suited for unit conversion, for instance, although units(1) would be a contender :)
M-x calc is pretty awesome. I had no idea it was there.. (M-x tetris I had heard of)
I use dc and bc on the command line. Some people have chided me saying the command line calculators aren't always accurate and are buggy, but I haven't seen any problems.
If we're talking online, WolframAlpha is amazing. Used to use it all the time. Now I use Emacs Calc, since it's built right into Emacs (a keybind away), and it's pretty nice and featureful.
I don't want another physical calculator but thanks for pointing me to Xcas. I haven't heard of it before, I must give it a go.
I've been using Mathematica for most of my computer algebra tasks, but it's not free. I've dabbled with Maxima and SymPy but neither are as easy to use or as powerful as Mathematica.
Emacs' calc can also be surprisingly powerful. Not quite at the level of Maxima, but still perfectly capable of basic symbolic algebra and calculus, arbitrary precision arithmetic, linear algebra, and other good things.
I use it quite heavily since it's right there in my editor. It's kind of like a good-enough phone camera that's always close at hand vs. a dedicated camera that's better but takes more effort to have ready.
It’s a really good engr/sci calc for iOS/MacOS. Unless I’m going for a specific need (Gotta have this exact HP compatibility, need funky plotting, etc) this is what I reach for first.
I know it's a very general question, but can I ask what sort of calculations you perform using Mathematica? Every time it has a new release, I download the demo and play around with it, but I never get as far as using it to actually compute anything that other CLI calculators couldn't do.
I tend to use either a command-line calculator (to minimise context switching, for simple calculations) or a physical TI calculator for simple matrix calculations, CAS features such as analytical derivatives simple integration, and dimension analysis (which is vital in my corner of Physics and very rarely done properly in software calculators).
If not maxima, then the old M-x calc will usually do the job
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