I have an old HP 15C RPN scientific calculator.

- 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 can't think of another electronic device that has survived and remained useful for half the 43 years my 15C has - through two years of high school, a math degree, and an entire software engineering career. When I calculate something any other way, it involves thinking about what my thumbs automatically do on my 15C and translating that.

When I'm away from it, there's a wonderful emulation of the 15C (and 16C) at https://jrpn.jovial.com. The numeric algorithms behave identically as far as I can tell, and it even includes the back panel (3-dot menu near the logo, then "Help"). The visuals make me feel right at home. If only they could reproduce the tactile experience.

I've never owner any other piece of technology with buttons this good.

It is really a lost art.

I use it while learning mathacademy

Yes. HP-11C. Who cares about the speed of the calculating device when I'm just adding or multiplying a few numbers? Physical buttons are easier to use than mousing on a screen. And it's highly portable.

- I have a HP 16C, mainly for doing number conversions (DEC-HEX-BIN) and binary arithmetic.

- 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.

Neat collection!

Do you have advice on how to use those calculators with modern tooling? For example I remember there were cross-compilers for the hp48 [0], do you use any of that (and how do you transfer data to/from the calculators)?

[0] https://web.archive.org/web/20250124204959/https://sourcefor...

No, I do not get that deep. I used to exchange data on the Ti-92 plus and the Classpad. Connecting those devices is either rather outdated (serial port with USB converter) and/or comes with vendor subscriptions, which I am not willing to pay.

Maybe, if I had more time ;-)

My 30-year-old TI-83 from college is still chugging along. My kid uses it for school. Math homework is all pencil and paper so having a physical calculator is more convenient. It’s portable and dedicated to a single use that it does very well.

There's a farm here in Zurich where we buy a lot of our groceries. The store is unmanned. You use their calculator (or your cellphone calculator) to add up what you're buying then use your phone to scan a QR code and pay.

That’s so cool, I wish something like this existed in the states. That’s the kind of trust local communities thrive in <3

I know a few farmstands here that operate on the honor system. Put $5 in the box, take your bag of apples. You have to go a bit out of your way, but they do exist in the States.

Lots of farm stands in NY’s North Country operate like this.

With Zelle, etc, there’s no box of cash sitting out and you don’t need to worry about making change.

These exist all over in the U.S. There are easily hundreds in my area, though I only frequent a dozen or so.

+1, every time we hike up a mountain and there's a help-yourself-fridge/shelf, we take 5-10 items and it's too much to add up in ones head. I use the phone calculator and pay by QR code.

I use a junky $5 calculator when I'm working with my mill and lathe. It's easier to have the little thing there at hand in the machine shop to do quick calculations than to have a whole computer.

I'm using a HP48G. [0]

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.

[0] https://en.wikipedia.org/wiki/HP_48_series

I have a Swiss Micros DM42, a modern clone of the HP42s on my desk and I have the plus42/free42 app on pretty much every device I own. Stack based calculators are great because the stack works as a little scratchpad when I'm trying to figure something out.

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.

SwissMicros calculators are absolute gem. Thanks.

They even have printed manual for DM32. https://www.swissmicros.com/product/user-manual-dm32

TI-30Xa still sits on the corner of my desk along with a pen and small notepad. I use it 2-3 times a week. Still faster to reach for it than find the calculator app on my phone or PC for simple tasks.

Yes, I have a Casio fx-9750GIII and I love it. I still haven't found an Android app or website that can do everything that I need (basic functionality), but in general:

- 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.

I think you accidentally a verb.

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.

There’s a 991CW 2nd edition out even. Because they’ve realised they forgot to make the different “apps” accessible by pressing a number button. In the original 991CW, you always have to use the arrow buttons to select the feature you want to use.

> I think you accidentally a verb.

Totally reminded me of the old meme "i accidentally a coca cola bottle, is that bad?" :D

To be more on topic: yup, Casio fx-85ES - still going strong, needs basically no maintenance at all and having tactile buttons you can mash while sitting over a piece of paper just has no comparison.

lol I did accidentally a verb yes, quite a frequent occurrence with me!

My HP32s from ~40 years ago still resides on my workbench where I mess around with RF circuits for fun. It has no graphing capability and it's barely programmable, but that's ok, I keep an actual computer nearby for those sorts of things. The calculator keeps earning new batteries bc tinkering with analog circuits I frequently want to evaluate little things like AB/(A+B) or 1/2piF or (1+S)/(1-S), or need the log 10 or square root or the cosine of something.

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.

Yeah I still use my good ol' TI-83+ occasionally, but I'm a math instructor, so obviously. Most often I'll just use GNU `bc` though.

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.

Yes! I’ve held onto my TI84 from high school and find myself reaching for it far more than I ever expected.

I have Sharp EL506T and it serves me well. I don't use it very often, mind, but it still happens semi-regularly.

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.

Sharp DAL calculators don’t get enough love. I see HP this and Casio that, but I’ll say that Sharps are a treat to use too.

Absolutely!

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.

I don't, but I sometimes see them used here in Japan. Some small-shop operators use them to add up charges and show the total to the customer. I was recently in the office of a small company, and I noticed that the bookkeeper had a calculator next to a pile of paper (receipts?) on her desk. She also had a computer in front of her with a spreadsheet on the screen.

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.

[1] https://maps.app.goo.gl/nvTg4hfSjTcba47c8

> There's still an abacus school

(I'm in the US) I remember being taught how to use an abacus when I was in grade school. Not kidding. I'm not so old that they were used anywhere in real life. I believe the whole point was to teach different ways that calculating can be done. A little horizon expansion.

Yep. College requires a TI-83 and I use a DM-16L for accounting homework.

I still use my dad’s old HP 15C. Form factor is good, aesthetically it’s very appealing, it feels efficient to use, I like the tactile feel of the buttons, and I like thinking of my dad when I use it.

During my bachelors, I was using a Casio FX-991ES+. It was a beautiful calculator compared to the hand-me-down Fx-82 VPAM. And pretty popular with the folks of my age that time.

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.

I still have my Casio FX-83MS which my mother purchased for me when I started secondary school 24 years ago. It still works, it usually sits on my desk, and I use it a couple of times per month.

Yes, not for its technological features but for its single-purpose-ness. If I'm working on paper, it's nice to pull out rather than a full on computer which also has all of my email on it.

I keep my ~25 year old Ti-83 or 84 from middle and high school in my shop because I find using it while working on stuff with dirty hands much easier than my phone or tablet. I just need something which basically never needs new batteries and lets me use parentheses to group expressions and the occasional trig function. I think the current batteries are almost ten years old now.

Oh dude, no. The instant I could start using something like https://www.wolframalpha.com/ in college over a decade ago, I did. I've never, not once in my life, had any desire to use a physical calculator when I could use a full blown computer instead. I think it's inferior even for pedagogy purposes - I can't screenshot and make Anki cards out of a TI-84.

I tried using my WolframAlpha in high school but I had no idea what I was doing and it felt way too complicated, but in college it is a game changer and I still use it to do school work. Totally agree!

I use a Casio. Not just calculator, but for any tool, I try to avoid using my phone. A phone is a rabbit hole. Once you pick it up, you never know what notification will interrupt your flow. Besides, for these utility apps are difficult to monetize, it's hard to find one that isn't bombarded with ads. Even if luckily you find a perfect one, the creator might lose interest and stop maintaining it next year, forcing you to change your usage habits.

I still use a high school calculator for doing pen and paper maths. Stuff like figuring out when functions change sign. I find it less distracting than a code editor

The first time I went to China and spoke basically no Mandarin (just "want", "don't want", "this one", "that one", "how much money", "thank you") I took a cheap calculator when I went shopping for electronics and just let people type in the price they wanted. It was also useful for haggling too.

Yes. When accounting I use a cheap calculator to do quick sums. Easier than using a calculator on the computer desktop.

Yes, I do. At my workbench, I find them much faster and more convenient than using my phone or a computer.

HP-42S; cold dead hands; etc.

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.

I use an emulated scientific calculator Android app which has all the features of a physical calculator but none of the performance issues.

If I'm at my laptop, I usually just use a IPython REPL.

I use a SwissMicros DM16L (a HP16C clone) because I like RPN and prefer physical buttons over a touchscreen.

Oi! You forgot adding machines. Big buttons, +/- features, auto-tax. And! Inexplicably none of the pre-installed calculators emulate them—bizarre.

And yes, I do use an adding machine, Sharp EL-1750

Nope, spotlight search handles basic calculations, python repl the rest of them.

I still regularly use a TI-35, and / or an old slide rule (I have three), and / or rough mental order of magnitude guesstimates.

Otherwise I use domain software for other tasks.

I use a Casio HL-815L to manage my checkbook. I lost the ability to do this math in my head about 10 years ago. I am 77.

I keep my TI-84 at my desk and reach for it maybe once a week. Usually for money reasons though, not so much for work stuff.

Button feedback, reduced chance of fat fingered mistype. Doesn’t tie up phone holding numbers on screen.

Haven't used one since the day I finished school. I still have it though. It's like an artifact from another time...

Does Windows Calc.exe count as well? :-))

I do. It just works, and it feels better than the on-screen versions. The Windows calculator is atrocious. Some of the emulators for iOS are good, but still feel clumsy in comparison to the real thing, especially for more than adding two short numbers.

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.

My kids often use their hands, I sometimes use paper and pencil

Mines are stored, but I use the hp48 emulator regularly.

For over a decade I've been using emulators of the calculators I grew up using on all my android phones. I see no point in changing my "weird" ways.

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.

HP-16C

Casio fx81

I use only the HP once in a while for old times sake.

I still have them, also a slide rule, but no, I don't use them. It is essential to have these for when the grid breaks like it currently has in Mississippi for over a week. I also have multi-decade-storage batteries for them.

I actually own one, a Casio. Simple reason, I'm a ham radio operator and you need one for the exams.

FCC license exams I am assuming?

I'm German, but yeah, our version of the license exam.

To add to the original question, even for normal operations (e.g. calculating exposure limits), I prefer the "natural" way of entering a formula with fractions over having to manually think about braces like I'd have to do with the macOS calculator.

tl;dr: RPN - ride or die. ;)

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.

"Do you still physical calculators?"

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.