HP HP48GX RPN Expandable Graphic Calculator

Amazon Price: $265.00 (as of January 29, 2015 6:16 pm – Details). Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on the Amazon site at the time of purchase will apply to the purchase of this product.

Item Name: HP 48GX (128KB) graphing calculator – used. Cosmetic Condition: Good Perfect Working Condition HP 48GX Expandable RPN Graphing Calculator with two expansion card slots This item has been discontinued by the manufacturer. We have a limited number of used calculators available at the price listed on this page; once they are gone we'll likely stop carrying this model. These used units have been verified by us to be in good condition and in working order. Includes cable and batteries. Does not include: Manuals or manufacturer warranty. Returns will not be accepted for this item, but we will repair or replace defective units for an extended period of 60 days.

Technical Details

  • Over 2,300 functions including over 300 for scientific and engineering applications
  • Built-in equation library with over 300 formulas and constants
  • 2-way infrared communication, RS-232C serial port; supports optional printer
  • 128 KB memory; 2 card ports for expandable RAM and ROM
  • 2-D and 3-D graphing capabilities

Product Details

  • Product Dimensions: 1.2 x 3.2 x 7.1 inches ; 1 pounds
  • Shipping Weight: 3 pounds
  • Shipping: Currently, item can be shipped only within the U.S. and to APO/FPO addresses. For APO/FPO shipments, please check with the manufacturer regarding warranty and support issues.
  • ASIN: B00004TFKZ
  • Item model number: HP48GX
  • Discontinued by manufacturer: Yes
  • Date first available at Amazon.com: May 9, 2000

Customer Reviews


 April 22, 2001
By H. Kyu
For a serious electronic engineering student in his senior year in college, calculations extensively revolve around converting units including bases as well as vectors. Compared to it’s competitions from TI, it is such a no nonsense super-powerful engineering calculator that even the TI-92 doesn’t come close to what this 48-GX can do. Entering numbers in RPN format may be quite tricky at first, but after about 4-hrs later, I came to prefer this format over the algebraic one. RPN totally eliminates the need of parenthesis. Algebriac fans can do algebriac entry and/or display too. It has a massive expendable equation library, so there is no need to carry around a ton of formula sheets. I also own a TI-85 and a CASIO FX-115W. Other than not being able to graph, the little $20 CASIO is much stronger and capable than the TI. It can do integration, derivatives, and can easily convert bases (HEX, BIN, DEC) and vectors (POL, REC). Up until I bought the 48-GX, I only used the CASIO. Now I don’t have to use the CASIO anymore. I did some comparisons with my friends and found out that this HP calculator has all the ability of a TI-89 and a CASIO FX-2 as well as the usability of a CASIO-FX-115W, in addition to many more features, including easy expendable memory using cards which can be used like floppy disks to store infinite data, alarm clock, dnld and play music, x-fers to other 48-G/G+/GX by means of infrared light, symbolic calculations that can be converted into a numeric answer in one step, add/sub/mul/div polar and rectangular formats together in the same step, and don’t forget the UNDO button when something goes oops. This is only to mention a few. It comes with an intro manual, and a very good comprehensive manual. If you are an engineer or a serious engineering student, one day alone with the 48-GX is all you need to famaliarize yourself with it, and chances are you’ll never go back to a weak and overpriced TI again. If you don’t need 3D analysis, HP-39G or CASIO FX-2.0 is recommendable, which are equal to TI-86. If you don’t need graphing, CASIO FX-115W is a good choice.

The Mercedes Benz of Calculators

 January 11, 2004
By Ken Bourque
Being a college professor of Electrical Engineering for over 30 years, and having used numerous brands and models of calculators and having written reviews of some of them for various publications, there is no doubt in my mind that the HP48GX is indeed head and shoulders above all the other calculators (even the HP49). The RPL entry system is a natural and easy to learn process that mimics the pencil and paper approach that we’ve all learned in Grammar school arithmetic. The efficiency of input and the ease with which it handles comlex-number calculations is second to none. Formulae can be entered with mixed units and the calculator automatically performs internal conversions to present the answer in whatever valid units you desire. It handles 2-D and 3-D vectors with all the corresponding mathematical operations seemlessly. The infrared connectivity (wireless) and RS232 port (wire) both allow communication between another HP calculator and your computer. This calculator has the right mix of ‘function per key’ versus ‘menu per key’ that makes it very easy to negotiate.
One can enter a formula in algebraic notation and the calculator can solve for one of the variables in symbolic and/or numeric form (if all the other vales are specified). The keystroke error recovery facility is superb. A couple of days with this calculator and most people cannot go back to their old ‘Algebraic Operating System’ calculators, with its cumbersome parenthesis, without making a mistake.
There is not enough space here to praise this calculator to the extent that it deserves. Over the years with all the students and professionals I’ve had contact with, I know of no one who has ever regretted purchasing this calculator except for the fact that they realized that they waisted money on purchasing their AOS calculators.

The best calculator in the world

 February 22, 2002
This an incredible machine. Has a bit of a learning curve to be able to harness it’s power, though. Has unit conversion, terrific equation capability, and probably more software written for it than any other calculator in the world. If you just need basic calculator functions, however, this isn’t the one for you. Also, if you’re not familiar with RPN (reverse polish notation, i.e. 4 ENTER 5 + displays 9, instead of algebraic 4 + 5 = displaying 9), then you should avoid it; buy a cheaper RPN machine 1st and see if you can adapt to it. RPN, however, is far superior to algebraic notation once you get used to it. Do NOT waste your money on the HP 49, which I also own, and can’t stand. The HP 49 has rubber buttons which are hard to press, and a bizzare color, and is very difficult to use.

HP48GX – Highly capable, reliable, robust!

 December 3, 2001
By C. J. Carter
Hewlett-Packard’s HP48GX is an excellent RPN calculator packed with just about every mathematical tool you’d need to handle a huge range of engineering and scientific work. Initially somewhat daunting in use – almost every key has multiple functions, and you *do* need to refer to the printed manual for the first week or so – it quickly becomes an indispensable tool. For years before I got this device, I was a loyal Casio user with a number of FX-series machines to my name – and a sneaking suspicion of RPN (I knew too many ‘RPN zealots’ who would sniffily remark: ‘Well, it’s the only thing to use, you know…’) – but a friend showed me in literally ten minutes how quick and easy RPN can be, and I was hooked. It is just the same method you use when you calculate anything ‘by hand’ – and for those of you without handy buddies to provide lessons, the manual gently introduces the concept to you in a few simple exercises. Don’t be afraid…
On the hardware side, the unit is very well made and robust; casual knocks and bumps won’t worry it. Keys have a positive feel, the display has good contrast and uses legible fonts. If you need things to work reliably under rather non-standard conditions (as I do), I’m happy to say that my HP has performed reliably in sub-zero temperatures and at altitudes of up to 14,000 feet for weeks on end, without a glitch.
A tip: if you are not upgrading from an earlier HP calculator, I would advise you to pick up ‘The HP48G/GX Pocket Guide’ by Chris Coffin and Thomas Dick (ISBN: 0-931011-45-0) as a companion to this machine. It fits in the calculator soft-case and has *a lot* of useful information on the plethora of functions available.
Highly recommended – especially at the discounted price.

Stack is different. This required learning

 April 25, 2004
By Ross Bagley
To store ‘5’ on the HP48 line of calculators, hit 5 [enter]. It’s stored. You can even see where it’s stored right away because you’re always looking at the bottom four stack entries. It seems the previous reviewer believes that the way TI does calculators is the way calculators should be done. If that’s you, buy a TI. Storing a value in a named variable is a fundamentally different way of thinking about calculation from the way HP decided to do it.
With RPN, there is very rarely any need for a named variable and it only took me about an hour to start using this calculator for fairly complex EE homework. One of the things I noticed about RPN fairly quickly is that if you’re doing complex calculations, you’ll often build up intermediate values and then bring the intermediate values together at the end. My study-buddies were always writing down their intermediate values, I just left them on the stack while I did the other calculations. More often than not, those previously calculated values were exactly where I needed them when I needed them later. Everyone else was punching back in the values that they had previously written down (with the possibility of error on each transcription) or trying to remember which variable they had stored them in.
I don’t mean to ding the TI approach, I used to work at TI and I think they make a great product. I simply think that the HP has a subtly better philosophy of calculation and a massively better keyboard in the 48s/sx/g/sx line of calculators.

I carry this thing almost everywhere

 March 14, 2002
By Joseph Bullough
I’ve been using the HP48 series calculator for more than 10 years, starting with the original SX model during my college days, and later upgrading to the current GX model. Since I’ve never used any brand of calculator other than HP I can only judge this model on its own merits. The 48GX is an amazing and powerful tool. It has been by my side through countless college exams, homework assignments, the FE and PE exams, and my current profession as an engineer. The beauty of this calculator is that the more you learn about its operation and functions, the more powerful it becomes. Writing a short program to number crunch or perform routine calculations is a breeze. Like any other calculator, this unit will not make you smarter, nor will it solve problems you couldn’t otherwise solve, but it will greatly assist in countless calculating and programming tasks. I would recommend the HP48 as an indispensable tool for a student or professional in the math and scientific fields.

Top of the line (but an older, slower unit), fantastic HP calculator

 June 13, 2009
By Ann E. Revelle
I have owned top of the line graphing and scientific calculators from TI, HP, Casio, Sharp, etc. Back when I was a student, TI’s were very cheaply made and often broke quite easily amd similar HP products lasted almost forever. This machine, the HP48GX (graphing and expandable), continues that HP tradition and is definitely put together very well. The HP48GX also includes the full and very extensive library of solutions from various branches of Physics and Engineering, etc. The pros and cons as I see it are:


1) The Hp48GX has all the standard regular features plus CAS (Computer Algebra System) features that we have come to expect on such a machine, plus many nice very detailed and topic as well as course specific APPS that are already preloaded or can be added in electronically and quite simply from the HP or HPcalc or other websites.

2) It even works quite naturally with complex number solutions of equations (it can be switched from a real to a complex operating mode and even back again as desired). This machine is so versatile however that it will even evaluate symbolic matrices and it even evaluate the physical units of extremely complex equations as well as its numerical answer(s) (see more discusssion on this topic below).

3) This machine itself is relatively slow compared to the HP50g for example, but still comes with a graphical interface and resultant plotting system. The resultant plots are high quality and are very intuitive for the learning process.

4) It has a nice old style rectangular body design (similar to the Casio FX-2.0 or FX-2.0Plus) that sits very nicely both on a desk or a table as well as in your hand.

5) It has a large on-board main memory (by 1992 standards) that can be readily expanded and that is enough for tackling some memory intensive problems.

6) Although it is called a calculator, it is really a small, handheld computer system which can tackle problems from the most simple to ones with quite complex features.

7) The famous RPN (Reverse Polish Notation) operating system is available to the user.

8) The complete set of the predicted units of the solution of a complicated equation (or set of equations) can be determined independently of and simultaneously with its numerical answer(s). This is a feature that I do not know of on any other calculator system (except the later HP49 and HP50 series).

9) As on all such HP RPN models, a very fine self-test system is available to make sure your machine is fully functional all the time and a reliable clock (with seconds) is also continuously available.


1) Some functions that you would readily expect to be available with a single key press require instead at least two key presses, but usually with only a single shift key press first.

2) The learning curve is quite steep, although very well worth the considerable effort, but this will heavily deter some good students from learning the RPN skills that can be effectively used for your entire lifetime once they are successfully mastered.

A great tool for engineers! (Too bad for the lousy manual)

 June 2, 2000
By Carlos Augusto Narvaez
The HP48GX is an amazing calculator…. It has an amazing and easy to use built-in Equation Library (with graphics and variable description), its graphical capabilities are astounding. Even the Integration/Derivative functions are really nice to use.
The only flaw that I noticed: The user’s guide is quite poor regarding the programming capabilities of this excellent calculator…. I have to program and solve the formulas one by one and then relate the results that I get to other formulas, instead of performing a single program that will take to the answer that I’m looking for… Don’t get me wrong on this: The HP48GX can perform programs, what I mean is that, based on the user’s guide, I have no idea on how to do this…..
If the guys at HP deliver the HP48GX with an user’s guide that includes advanced programming, we have a 6-star device, way ahead of other calculators.

HP48 Review – For Electrical/electronic engineering

 February 27, 2003
By Simon WARDER "SimonW"
I am a electrical/electronic engineer working in a research laboratory, and have 20+ years of calculator use behind me! I have owned HP calculators since the earliest days and an HP48 series for many years now.
Although expensive, value for money is very good given the quality, performance and longevity on offer.
Plus points – RPN logic; wonderful tactile keys; display – especially display of the ‘stack’ which holds intermediate results when evaluating a long formula; equation solver and associated graphing; ease of ‘everyday’ programming; matrix entry tool; complex number, vector and matrix math are as easy as real number math with no special ‘modes’ to set; numerical integration of functions; analytic solution of integrals and differentials; directory structured memory for user programs, functions and data; user definable ‘soft keys'; PC connection for backup & programming. The solid construction – mine works very hard and is still as good as new.
Negative points. Graphic functions and especially the graphical equation editor can be slow. More complex programming needs study of the programming language and the manual open beside you – but is very powerful. Bit bulky for field trips (I have a shirt pocket HP-11 for that – discontinued now I think). My version of PC software is a bit clunky, but current offering might have a much newer version
It uses RPN, which I prefer, as it is logical and efficient – but it does take a little learning and some people just don’t like it. I believe it is worth the effort, especially at the start of a career. My calculator is used to make real engineering decisions – so I don’t trust many ‘algebraic entry’ calculators where sometimes it is not clear how complex formulae will be interpreted. This is particularly true of the newer generation of algebraic calculators that advertise ‘formulas entered as you would on paper’ (i.e “Sin X” instead of “X Sin”) I find they often have inconsistencies (e.g square root operates on the subsequent input, but 1/x operates immediately on the number in the display, as does x! [factorial x]) These inconsistencies have to be remembered to avoid possibly serious and unnoticed errors. RPN has only one rule – a function executes as soon as its button is pressed (or it is reached in a program). The famous HP stack which stores – and displays – arguments and intermediate results replaces the use of brackets and is far more flexible. Together these features, and others – like the ease of recovering from your errors – put you firmly in control all for the cost of an hour or two of learning. But, as I say, some people don’t like it so newcomers would be wise to find someone to demonstrate RPN before buying.
In summary this is the best calculator I have owned, and probably ever will as some reviewers say the newer HP products appear to have moved down market in terms of construction and ergonomics – but I have no experience of this.
PS I have no connection with HP, other than 25 years of good
service from HP calculator products.
Oh, yes. Some reviewers say the beep can’t be turned off, keying MODES -> BEEP works on mine!!

A fine tool

 August 17, 2001
By Neil W
I purchased the 48GX’s predecessor, the 48SX, 10 years ago. It took a week or two to get used to the RPN, and ever since I have loved it. It’s like owning a buckwheat pillow. Once you’ve had it for a while, you’ll dread ever having to go without it. The 48GX is not the newest thing on the block. There is the 49G now, which some have commented lacks the solid feel and quickness of the 48. Some convieniences, like unit conversion, are also harder to get to on the 49. Years after the creation of the 48, TI finally managed to catch up with its power and flexibility when they created the 92, so you’ll also want to check out that one. But as an expandable, programmable analytical machine, the 48 remains a top choice.

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