- I know where the buttons are without looking.
- It has functions my Android calculator does not have (directly or that I know of).
- It has a strange satisfying tactile feedback.
- It never interrupts me. Ever.
- It never distracts me. Ever.
I reach for it frequently.
- I have a HP 15C to take with me all the time (due to its small form factor).
- I have a HP 48 GX as main calculator, it is most feature complete and has a clock and alarms. I use it a lot for time calculations.
- I have a HP 48 SX, but did not use it much any more after acquiring the 48 GX.
- I have a HP 10bII+, which was a gift of my brother in law when he saw my obsession with HP calculators. I do not use it much, as I am not in financial stuff.
- I have a HP 41 CV, which is less capable as my 48 GX, but I somehow love it so much, that it resides on my desktop and is used a lot.
- I have a Casio Classpad fx-CP400, which I use when I tutor my nephew - it is the best fit for high school requirements (in Germany).
- I have a bunch of TI nspire and voyagers and a TI 83 plus, that I never use.
- I have a TI-92 plus which I used a lot in the past, but I do not like it anymore.
- I have a Casio FX-730P, which I like to write little programs for.
Not to mentions my collection of slide rules.
- I need physical buttons. I often find that on touchscreens I mistype something and I don't notice.
- The history feature. Maybe I want to do a serial task or calculation, and I can just replace/correct one of the formulas in the history and it automatically recalculates all of the expressions that came after it.
- I have written some micropython code / utilities for the calculator and I use it all the time.
- I don't want to context switch to do a quick calculation. On my PC I have to open up a new terminal or a website (I might be offline, so I have to hotspot and then connect the wifi and ...) and interrupt my existing work or I have to frequently switch between a PDF or latex or whatever that I'm working on.
- Typing out `sin` or `np.sin` or `sin^-1` on PC is both longer and more error prone. It gets very frustrating very quickly.
- The numerical solver is a godsend. Try solving for the roots of an expression like `xe^x = 10` on your PC without internet. Or with an android application. On my calculator it's just a few dedicated button presses. On the PC, I have to use isympy and typeout `nsolve(Eq(x * exp(x), 10), 1)`, and you wouldn't even get a proper graphical display of the expression while you are typing it.
If I'm solving a problem of any complexity I'll move to a more appropriate tool like python or a spreadsheet, but for the simple math that needs to be done around the edges personally and professionally, I like a calculator. If I'm at my desk, I'll use the physical version.
It's just a joy to use and i also like it a lot design wise.
I like that it has a big display for 4 RPN rows, but i admit that that's something software calculators would even be better at.
It definitely has a nostalgic/romantic side to it for me.
Oh and for every day stuff, i really like to use Spotlight on macOS. It's really convenient: Command+Space, then just type the expression into the search box.
But, yes. Casio fx-991EX. It's designed for schools, I think, but at the time it was the most advanced one they made that wasn't a graphing calculator, since I figured that if I ever wanted to draw a graph I'd just fire up "Grapher", which is still bundled with every Mac.
In about a decade I think I've done that once. The Casio is great.
Looks like it's discontinued now? I guess the fx-9910CW is the replacement. They made the buttons circular. Weird.
Today two cheap calculators are available to my children mostly as an example of "productive technology", in contrary to modern devices. This falls under a general effort to expose them to productive paradigms of 80's way of life.
We are getting away from them in the classroom though; just started piloting a program where students use the Desmos app on their phones (requested to be in airplane mode) in class, and we have a department set of air-gapped phones with Desmos pinned for students to use on exams.
In those circumstances, the calculator's compact form factor is quite convenient, compared to needing two hands at the computer keyboard, or one handedly hunt-pecking said keyboard. As for the mouse, that has to be the slowest, most focus stealing option of them all. The calculator doesn't take much room, so it can be kept within arm's reach without getting in the way, quickly gives me the numbers I need, without demanding I become fully engaged with it.
Also, those old HP buttons are just so nice to press, a refreshing break from the dead flat glass you get everywhere else these days.
The biggest reason for me are physical buttons and the fact I know the layout and capabilities. I'm just faster on physical calculator than on Android app.
But to tell the truth, usually I just use Speedcrunch on my computer. Or spreadsheeds. Or Python REPL.
I use RealCalc for most things (RPN style). Has many functions like a scientific, but I mostly stick to the basic four and it also converts units.
I switch to Graph89 when I need a graph/table involving trig or polynomial approximations. Sometimes I'll even write a basic program. If I'm using this app I probably also have measuring tools out for a DIY project.
I go to spreadsheets for anything beyond that using "Office: Planmaker". It handles the xlsx format perfectly! That's how I do my monthly budget, health tracking, etc. For reasons beyond my understanding, some people are still impressed seeing proper full-featured spreadsheets done quickly on a phone.
When I moved here forty-three years ago, it was common to see abacuses used in similar situations. There's still an abacus school [1] not far from where I live, but it's been a long time since I saw one in use.
Why?
Satisfyingly-clicky real buttons in memorizable positions
Easy to grab without thinking
I have a functionally identical emulator on my phone, which is far better than the built-in calcualtor, but it's a supremely dissatisfying substitute for the real thing.
As for why I use them?
- They are tactile.
- They are forgiving, pushing a button doesn't accidentally swipe to some random app or screen or slide down notifications.
- The physical calculator doesn't interrupt my work with a notification or popup.
I realize it makes me a boomer, but using modern smartphone interfaces, especially post-home button iOS, feels like interacting with a UI sitting on top of a banana peel. Buttons now require more precise and well-timed touches to activate their actions (eg: the buttons on the lock screen). I frequently find myself accidentally swiping between apps or navigating to new views.
I really wish I could go back to the old way of having a singular app be the focus, and having a home button or something I can press to switch between app contexts, without all the easily triggered and hidden gestures.
During and after grad school, I was using Mathematica or NumPy/Sympy quite a bit. But it felt like using an overpowered system to do basic assignments. Think of taking a Bugatti Veyron for grocery shopping. I indulged myself with another physical calculator - this time a Casio FX-CG50 with a color display and python support. I use it whenever I do self-paced courses or reading the occasional stats/ML paper.
Great battery, that.
It's like having a second monitor, just for math, and you can take it with you. Modern technology is incredible.
On my desk I have an HP-28S and use it nearly every day.
In the office I have a newer HP, which isn't quite as nice to use as the 28S but still quite good.
The ergonomics of these are so far superior to using software apps that there is no comparison.
Citation needed. They are pretty clunky, unless you have a numpad typing on them takes way longer. Graphing and fast access to mathematical functions is way worse.
I mean I do substituted my calculator with the computer, but the replacement is Python and GeoGebra, not the built in calculator. And the reason is mostly convenience of not replacing batteries. I do use the standalone calculator while the batteries are full.
If I'm at my laptop, I usually just use a IPython REPL.
And yes, I do use an adding machine, Sharp EL-1750
Sometimes, for vintage reminiscing, a real HP48GX.* It got me through AP Calculus BC, SAT-I, and EE/CS. And doubled as a learning TV remote & TV-B-Gone. I also have a virtual HP48 on my phone, tablets, and computers.
In middle school, I had an HP 32SII. I remember being able to hear** either the processor clock or data line(s) of each of the 32 and 48 because one or more components acted as inadvertent audio oscillators that would make noises during computation (and during idle on the 48 because it had to keep redrawing the clock).
I've used R, MATLAB, pspice, and Mathematica in the past.
I'm a fan of Xcas and Wolfram Alpha now.
* I also have a collection of HP 48[GS]X cards, the printer, and the overhead projector adapter. In lieu of the overpriced official HP 48G to computer RS-232 interface cable, one can be easily made from a Sony CD-ROM audio cable.
** With my much younger ear pressed up to it.
Otherwise I use domain software for other tasks.
Here in NL - Casio FX-82NL is allowed during test/exams for middle/high school, and actually for Radio Amateur/HAM licence exam - they even hand you one of their FX-82NLs.
Other more advanced (graphing, with memory/Python/etc) are also allowed in some places, but they need to be set to exam mode that disables memory/python/etc.
The truth is: I like calculators, and I think almost everyone answering in the positive does too. Most people don't care about them, and see their phone as a god-given miracle, I guess, which makes calculators an expensive-ish burden.
Casio fx81
I use only the HP once in a while for old times sake.
Well, no. My calculators don't bounce around so I have no reason to "still" them. /s
I have a calculator app that I use 99.9% of the time. I have a physical calculator around here somewhere. I used to use it when I'd have to tabulate physical items or when I'd been doing calculations for a long time. Short bursts on my phone are fine, but over hours is kinda troublesome.