Which calculator? I would like your advice


Hello folks,
I have hung around this forum for about three years now, posting occasionally, but for the most part just reading others' posts. You folks are very knowledgeable in regards to this subject, so I hope to gain some valuable insight with this post.
I have returned to college after almost 20 years. During that 20 years I spent time in the military and held down a few non-technical jobs. I'm currently working on a geography degree and entertaining a second degree in mathematics. Teaching at the junior college level seems like a nice niche and I can do this with just a Master's.
In 1987 (my first year of college) I bought a HP 32s and only lightly used the thing. It traveled with me during my stay in the army, but mostly just sat (unloved) in a desk drawer. The RPN idea seemed nice and the 32s always seemed like a wonderful machine, but I really had no reason to use it other than for simple calculations. I knew nothing else about the HP calculator line as I was still in high school in the early-to-mid 80s.
Fast-forward 20 years and now the great HP calc is pretty much deal, with nothing but a few "zombie clones" passing themselves off as HP calcs. Nonetheless, I am considering a 33s and a 49g+ as day-to-day machines for my studies.
I currently have the following HP calcs (15c x 4, 16c x 1, 11c x 1, 27s x 1, and a 32s x 1). I only plan on keeping three at most, but if they are vintage machines, I want them to be in solid condition. OR should I sell them all and just get the new "HP" machines and call it a day? EXCEPT for the 27s as I love that calc.
So, what will I really need for a Geography and Mathematics degree...calculator wise? It would be easy to fall into the nostalgia trap (as I did with the use of the MINIDISC format) of the vintage machines, as they are built so well, but in the long run does it really matter? Or would I be better severed with just a 33s and a 49g+?
Any and all opinons are welcome. Thanks in advance.

Joe Edwarads


1 + 1 still equals 2 (or 1 1 +, if you please), so your current stable of 15Cs and other delectable vintage gear should do all the math a calculator should do. Graphing and other stuff is better done on a computer, IMHO.

FWIW, I just got a 33S yesterday and I think it doesn't suck. Once I got past the silly cosmetics (and hard to read keyboard legends), it's everything I want in a calculator: good keyboard feel (much better than my 49G+, not as good as my 12C), nice easy RPN keystroke programming, ample memory, 2 visible stack elements, etc. I wrote a Gregorian -> Julian date conversion program without looking at the manual (much), right after opening the box, and it was actually fun.

My 49G+ is for sale since I really don't have the inclination to invest so much time in learning a calculator when I have access to much more powerful machines like the iBook I'm typing this on.

It's really just personal preference, I think: try *all* the options, which is an excuse for expanding your collection. (I'd like to try a 15C, for instance!)


Hi Joe. I got my Master's in Geography 32 years ago and I am getting a second Master's in teaching now (Middle School math). Based upon the college math courses I have taken the last couple of years, what you will need is (I know this is sacreligious in this forum) a TI 84 + silver edition, and that will be way more than you will ever need in Geography. I love RPN on my HP's, but you will never need it in college.


What would be different if I just used a HP 49g+ versus a TI unit, as long as I know how to use it properly? What made you decide to go back for your education degree? Thanks.



Hi Joe. I guess the 49G+ would be sufficient for most purposes. The professors, however, will use the TI series, and there are lots of help resources available for the TI's versus very little for the HP. I have a 49G+ but I have never used it for graphing because the TI just seems easier.

I decided to leave the computer field after 28 years because I wanted to make a difference in the world, and I decided the middle school math classroom would be my stage. I am student-teaching right now, and I love it. The kids all say "hey, gray-haired dude, aren't you too old to be a new teacher?"


Hi Joe,

No matter what you do with your vintage calcs, if I were you I would keep at least one functioning HP15c and the 32S. They basically do all the math you will need, the 32S a little faster than the 15c. The 15c is a very versatile machine including calculations involving complex numbers and matrices in addition to a root-finder and numerical integration. Except for the matrix-calculations the 32S has similar features, however the complex number handling is somewhat limited when compared to the 15c. I have 15c and 32S units myself and as a scientist I am quite satisfied with both of them. If you would like to buy an additional calculator, I would choose a graphic one to complement the possibilities of the 32S and 15c, the 48 or 49 models being a fair choice.


Your 27s is probably the best of the bunch for general math and certainly more than enough for your geography. Many on this board think highly of the rest though (including me, but the 27s blows them all away aside from some higher end functions of the Hp15c). I wouldn't part with any of the rest myself(but you could sell an extra Hp15c or two and buy another Hp27s and/or a brand new Hp49G+)

The 27s is kind of tough to replace and you might consider buying a new Hp48GII or Hp49G+ and using in in algebraic mode. However, these calculators are not any better than a Ti-86 (and actually more awkward to use) if you do not take advantage of their RPN mode (many functions and features are much easier to use in RPN and flag 117 set).

It is true that most schools use the Ti-83/84 graphics calculator in their curiculum (they are nearly identical aside from I/O and extra RAM and some extra apps/programs included in the 84). They are not in the same league as an Hp49G+, but they are also much easlier to operate and use for the average user.

Since you really like the Hp27s, if you want a graphics, your best choice would be a Ti-86 or maybe even a Ti89. The Ti-86 offers a nice menu system, long variable names, like your 27s and a solver similar to your 27s as well.

Good luck with your shopping and let us know what you liked best.


Thanks for the info so far. I am glad to see someone else cares for the 27s besides myself! I guess I need to stir the pot a bit by adding another ingredient. What do you folks say to a HP 41c/v/x as a useable calc (with appropriate modules) versus say the 15c/11c or 32c (I don't have a 42s). Thanks.



You might also consider an Hp19Bii. It is very similar to the Hp27s with the added feature of both more buisness functions and more importantly, units conversions. And if you don't mind giving up RPN, the older Hp19B can be purchased fairly reasonably via ebay (the Hp19Bii has RPN, the plain Hp19B doesn't).

Something else to consider. And the Hp19B is fairly easy to buy and replace vs your Hp27s. Drawbacks: Battery door and fold out book type interface (some like this though).


I just took a look at the 17b and 17bii. That is one ugly calculator! To be truthful, I like RPN, but the 27s is hard to turn away from with all those extra features. I haven't found any of the new HP equipment very interesting. While I didn't spend the last 20 years in a career using the vintage HP models, I did buy one in '87 and have been hooked on the vintage HP design and the QUALITY of those "Made in USA" products. It just makes my head spin that 20 years later, we cannot (with better technology) make a product with the same QUALITY as the old HP units. I really doubt the current line of HPs will still be operational in 20 years...and IMHO no one will really care if they do. While shopping at the local office store I picked up a 12c and was disappointed to find that the thing weighed half(?) that of my 15c models...and it felt "cheap", if that makes any sense. Maybe another 27s will do and a 15c if I can learn to use it as well. Still, those old 41c models....sigh


I did not suggest the Hp17B or Hp17Bii, I suggested the Hp19B or Hp19Bii. These are business calculators with trig functions and units conversions.

The Hp15c is a well made tool that is appreciated most by EE's or others with a need of complex number, matrix computations and possibly numerical integration. If you don't need these features, the Hp11c or Hp32s do just as well. To get the above on an Hp41, additional application modules are needed. That is the charm of the Hp15c over everything else except for the Hp42s or an Hp41c with an advantage pac module.

Simply put, the Hp19Bii may be worth looking into for an easy to find RPN with all the niceties of the 27s (same calculator from a functional point of view aside from the lack of HEX, OCT, BIN, Dec conversions, and no algebraic precidence in algebraic mode).

If you do like RPN, the Hp 48G (older and easily available for not a lot of $$$$ on ebay) is an excellent choice. Nice Hp feel, kind of bulky, but has a great solver w/ all the features of the Hp27s as well as many more. If you key in your own programs or equations, 32K is a lot, if you buy a cable and download, 32K don't go far. But you can download a couple of decent programs and with all the built in features, it is a graphics that will last a long time. It is slow in graphing compared to the Ti line, but I don't use it to graph functions anyway. The newer Hp's are far faster, but aren't of the same quality and the new Hp48Gii doesn't offer the built in equation library of the older Hp48G either.


I just mistyped the model name. I meant that the 19b and 19bii are ugly, but hey, looks isn't what the game is about. Sorry for the confusion.


Well, Joe, it looks like you got a lot of advice that many of us took note of as well. After about 30 years using programmable calculators beginning with the TI59, I have grown with the maximum versatility. I like the 49g+ preceded by the 48 series, but I am no math major. I like to experiment with programs in such disciplines as forestry using multiple regression techniques to estimate yields; financial equations involving random transactions, both amounts plus or minus and random dates; Real estate investment projections. I also take photography equations to the field to confirm my choices of settings for depth of field in closeup photos. I am able to perform and verify some recreational calculus up to simple linear differential equations and a healthy list of symbolic integrals and derivatives. If I were into serious math as a second major, I think I would get something more fundamental to replace my slide rule from the sixties, something to assist me at the chalk board, something highly portable. From everything I have heard, the 33 series seems to fit your needs for now.

Let us hear what you decide and why,



You just hit on something of interest. I am learning to us a Soroban (a Japanese abacus) and would love to learn to use a slide rule. Any advice on a nice slide rule?



Any slide rule will do for the basics, but if you want to get fancy, get a Log Log Duplex Decitrig slide rule by Keuffel & Esser (K&E), along with the original manual by Lyman M. Kells, Willis F. Kern, and James R. Bland. The manual is excellent and will teach you the basics of any slide rule. It can be obtained inexpensively from ABEbooks.com if you do not get it with the slide rule itself.

Cheers, Tom


Joe, I have an old K&E Deci-Lon with 4 plus and 4 minus LN scales. It is great for estimating "LN+1" values for things like growth curves, half life calculations and compound interest problems. The best book for me in the sixties was the hardback manual that came with the slide rule, but it has no library of Congress number or ISBN. It has good examples of solved problems.

Brought back nostalgic stuff for me to break it out to get your info. You might locate one on eBay. The title of the booklet is simply "K&E Slide Rules," published by Keuffel & Esser Co. I remember our old badges of rites of passage strolling around campus wearing the foot-long scabbards containing one of those "mysterious devices" we serious students wore. Now they carry programmables and/or laptops in their backpacks. I'm green with envy just thinking of how much more time I could have spent on concepts instead of countless hours roughing out statistical data analysis with slide rules and old mechanical calculators.

An engieers supply store or college book store should have plenty of log/log engineer graph paper. Take two sheets of this and "slide" the nonlinear scales next to each other to set up divide by and multiply by situations and you will have the fundamental premise on which the slide rule is designed, ( LOG Y + LOG X = LOG XY AND LOG X - LOG Y = LOG X/Y. ) The LN scales are based on the premise that LOG X^Y = LOG X x Y, etc. These facts on which the rule is designed and the fact that engineering paper for log/linear, linear/log and log/log can display non linear curves as linear in the highest order helped me to understand how we can say that differential equations are considered linear if the highest order equations are linear, while all lower order derivatives can be non linear.

I hope this helps in your search for a good slide rule book. I would say that, as a calculator, the slide rule is primitive and obsolete while, as a teaching tool, it contains a lot of promise.
Good luck on your change of career!



I would say that, as a calculator, the slide rule is primitive and obsolete while, as a teaching tool, it contains a lot of promise.

Yet there are practicing engineers who still use slide rules in their daily work, even though they have calculators and laptops available.


"the slide rule is primitive and obsolete while, as a teaching tool, it contains a lot of promise."

I agree.

I used slide rules in high school and college - 1966-1970. Even now, 40 years later, there are two items that has stayed with me:

1. How to normalize numbers for calculating.

2. How to quickly do an estimate of what the answer should be. Had to know where to put the decimal point in the final answer.

I work for a design MEP enginering firm, and I find a lot of the young engineers do not know how to to quickly estimate the range of the final calculation. They are too dependent on the calculated value - even when the calculated value does not make sense from the input data.


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