Every Maker Should Have [Pt.40]...an HP-15C, HP-35S or a Casio fx-61F

3 scientific calculators for electronics buffs.
Support Roger on Patreon: / kainkalabs
Each one with unique features not found anywhere else:
HP-15C: www.hpmuseum.org/hp15.htm
HP "Voyager" Series with HP10C, HP11C etc.: en.wikipedia.org/wiki/Hewlett...
HP-35S: en.wikipedia.org/wiki/HP_35s
Manual: h10032.www1.hp.com/ctg/Manual/...
CASIO fx-61F:
www.usersmanualguide.com/casio...
Other recommended CASIO calculators for engineers:
CASIO fx-115D
CASIO fx-570 AD
Radio Shack EC-4032 (rebranded CASIO fx-570AD with solar cells)
Support Roger on PATREON:
/ kainkalabs

[@MrSchattka]

I own an HP 15C which I bought ~ 35 years ago and still use it daily. Best calculator I have ever owned.

[@frankteunissen6118]

Me too. Also bought 35 yrs ago.

[@user-fg6ro]

Is it still working today? (2023)

[@hansdevreught5459]

When the HP15C came out I bought one for my study. The best choice ever. I was the only student able to solve a really complex solution to a question to use arrays. I was the only student that passed the exam...

[@karhukivi]

I got the HP65 with built-in magnetic card reader in 1975 and it came in a hard case with spare cards, user manual and books on applications for statistics and mathematics. A soft real-leather belt case was included which I use to this day for my phone. The 65 stopped working after 25 years of daily use, the battery died, the charger was faulty, the card reader wouldn't work and the display was faulty. The books are a goldmine of formulae, and the programming steps they give can be used on the 41C and probably many other models with some slight variations. An amazing piece of kit!

[@johnhalley7114]

That li'l (i) above the COS key on the HP 15 got me through Vector Analysis in Electronics Engineering. Couldn't have done without it. Pure gold! (Also, RPN rocks!)

[@MrWaalkman]

That li'l (i) could get you n a lot of trouble if you forgot to take it back out of imaginary... :)

[@df9999999999]

@@MrWaalkman Yup!!!!

[@pev_]

The "goodness" of the keyboard of an HP calculator is no joke! If you are used to the fiddly keys of just about any other brand, getting to handle a genuine HP is a pleasure! The keys do not tilt, turn, flop or rattle. When you put your finger on a key and try to move the key sideways or press it lightly on the corners, most other calculators' keys feel "loose" but HP keys are solid, they only go down, with solid force that lets you know you have pressed it.

[@drk5orp-655]

Hp 12c is very good. Hp 35s is less clicky and more plastic but good still.

[@huge_balls]

You hit the nail on the head! Most people will prefer their phone calculator because they associate real calculators with mushy buttons. In that case a phone is better. HP keyboards are a joy to use.

[@4pickets]

Outstanding reviews! Thank you so much for posting this. I second Mr. Schattka's comment. I bought an HP-15C new in 1982 during my first year in engineering school, 42 years ago! I have used it my entire career with no problems except one trip back to HP to replace a cracked screen. Can confirm the battery life. I like it so much I purchased a second one online.

[@liberty4all508]

I use a hp 48g that is over 25 yrs old. I just ordered a 35s, mostly because of the rpn and the keys. also, it just looks super cool. Thank you for the videos!

[@outsideworld76]

I used a Casio fx-4500PA during my days in technical college. I still works!

[@joseph_donovan]

Beautiful. Thank you.

[@Crazytesseract]

One can program the impedance functions into a Casio fx-5800P, and use it in the same way. Requires a few extra key presses, but the 5800P is available at lesser cost!

[@JanPBtest]

HP-35S had a bug in its trigonometric functions which AFAIK was never fixed. This made me stop using it. And then I discovered SwissMicros and bought their DM42 (the magnificent reverse-engineered HP-32S) and never looked back. The best calculator ever.

[@JohnUsp]

HP-42S

[@Curt_Sampson]

Regarding calculations in different bases on the HP 35S (14:38): this is indeed a useful feature, but unfortunately isn't as convenient for programmers as it could be. Although in hex mode the SIN through 1/x buttons change to enter A through F, the calculator in any mode always assumes decimal input unless you expicitly add an "h" after the number for hex (and or "o"/"b" for octal/binary). Unfortunately, the fastest way to do this is still three keystrokes (blue shift, BASE, 6) which really slows you down when doing extensive input in hex. What they should have done was to make input use the currently selected base by default, and have you append "d" to use decimal input when in hex mode.

[@robertpeters2068]

The 15C-LE may not have the 15 year battery life (probably still around 4 to 5 years), but the processor is a LOT faster than the original 15C. Same with the DM15L from Swiss Micros. I have a 15C-LE and a DM15L (and a 35s) and use them all on a regular basis. Great calculators!

[@mbaker335]

This comes out a week after I brought a Ti-nspire cx CAS calculator. Very nice in itself though I have had to buy a book to get the hang of the beast. The HP-35s does look good so I may get one of those as well as I am less worried about losing it.

[@noth606]

Nspire CAS are extremely powerful and I am very impressed wit them, even as a HP user since 25yrs. I found the math templates to make it very simple to input problems, and the CAS is very good. The templates are in Calculate mode, press Ctrl+ menu, 8 there you have base formula layouts that you just fill in. I have the non CX one but the functionality is the same afaik.

[@Moonstalker]

I wish casio do a modernized version of the FX 61F

[@Hieloxx]

I used that calculator in High school.. Great memories!

[@hitbyligtning9661]

YEH I USED IT ALL THROUGH MY ELECTRICAL & ESPECIALLY ELECTRONIC ENGINEERING. Used it continuously till i broke the screen about 3 yrs ago. I couldnt find anyone who could repair the LCD screen Never ever been able to find another "FX 61F" for sale since. I had that calculator it for well over 30 years.

[@lenkapenka6976]

Excellent synopsis! Many thanks... I own an HP-16C.... fine calculator.

[@KainkaLabs]

Congratulations. The HP-16C is even rarer than the 15C :-)

[@drulli1]

HP-41CX rulez! I bought my in 83, still running

[@karhukivi]

I bought the CV in 86 and use it every day. I have a 35C emulator on my phone which is free and excellent, only complaint is that it uses the "European" system of a comma in place of the point symbol.

[@ffggddss]

≈ 21 min: Calculating resistances in parallel - and don't forget, what works for those, works also for capacitances in series! So that button has a dual purpose. Fred

[@DeGuerre]

We need a scientific calculator that works in darafs!

[@Crazytesseract]

Alright!

[@vatandas1542]

Imo the casio fx3600 Pv was also a good calculator. esp. Its programming on the go. I have been using 48gx and will never leave her until "the brick" leaves me. Thank you

[@StevenStaton]

I have two HP-15C units, one of which I bought for college in 1983. They both work like new, and the comments regarding the keyboard and power consumption are true. I picked up the HP-16C in 1984 during digital electronics class, and it is both rare and extremely useful in logic design. I bought an HP-35S when they came out, but like the HP-48 series, it is lesser quality (it *eats* CR2032 batteries). Get the 15C if you can, it is a mathematics powerhouse.

[@jbmbryant]

The Google App Store has an HP15C Android app (by HP) that uses the exact microcode as the original, plus the users manual and advanced functions manual are built in for about $17 USD. My HP15C got me thru college very nicely and I gave it to someone starting college. I miss it each and every day but hope it got good use.

[@I_leave_mean_comments]

18:00 "English and Espanol... seems to have been a special edition..." I don't know if you're kidding or not... but if you aren't, maybe people outside the US don't realize this fact: Since the 80s or 90s, almost everything produced for sale in the US that comes with a manual has it printed in both English and Spanish. Despite what many Americans may say, the US is a de facto bilingual country. It's not just product manuals in Spanish either, but if you go to any government facility, the DMV or any administrative building, all the signs and all the paperwork are available in both English and Spanish... at least in all major cities, and all cities in the Southwest and West. So... that Casio must have been for the US market.

[@ffggddss]

Pretty much, yeah. There are also a fair number of products sold in the US that have text in English & French. These are likely the ones marketed for US & Canada. And the ones that have English, Spanish, & French are dead give-aways as NAFTA merch. - Mexico, US, & Canada.

[@Luci_S]

"It's not just product manuals in Spanish either, but if you go to any government facility, the DMV or any administrative building, all the signs and all the paperwork are available in both English and Spanish" Good luck with the road/traffic signs in English in the U.S.

[@telesniper2]

1:37 Well those days are back again! I bought an HP-35s around 2010 for $40. Well they stopped making them a few years ago. I looked online at prices....$400!!!!

[@TMSBRANDA]

40-50€ is not too expensive for the HP-35s. I love it❣️

[@telesniper2]

They are collector's items now. $400 and rising! Glad I bought one when they came out.

[@christopheroliver148]

@@telesniper2 Really? I should get rid of mine. Having used the 41CV, 41CX, and a 42S, I thought the 35S was junk by comparison. Today, most would be better served by loading Free42 onto their phones.

[@coredump27]

My dream calculator would be a RPN fx-61F, with HP like keys. Maybe one day SwissMicros will make one.

[@themaritimegirl]

Awesome video, enjoyed it a lot. :) Just one little thing - you explained the inductance and capacitance functions a little backwards - their impedance is totally imaginary, and the real part is zero. The calculator is presenting the imaginary part when the j appears in the display. :P

[@rogeriorogerio1007]

"I'm the operator with my pocket calculator" - this video reminds me so much of kraftwerk :D

[@KainkaLabs]

I once saw them in their home-town Düsseldorf in a concert and was one of the spectators who could push some of the keys on their Casio in the final song "Taschenrechner" (pocket calculator)

[@maxheadrom3088]

The HP 15C is amazing - never runs out of battery. The problem is it's a collector's item now.

[@MrWaalkman]

I just got the HP-15C Collector's Edition. Fantastic reproduction!

[@rayc1557]

Since discovering RPN around 1981, I cannot use an AOS calculator for anything more single operation arithmetic. Absolutely treasure my 15C purchased about 1 year after the model became available. It was a lot of money back then. I have two 35s units for everyday use. They are good too but, the keyboard is a bit crowded.

[@markwales3630]

I have a 11C from 1987 that I use almost daily, and it is still in good condition (similar to the 15C but not quite as many functions). I also have two 35s calculators!. Like you I have difficulty using anything other than RPN. I even say I am addicted to RPN!

[@bblod4896]

I've owned my 15C since 1978. Still works. I also own the two user guides that were available at the time.

[@Crazytesseract]

Any signs of the reflective layer of the LCD fading/ darkening, after so many years? It happens quite often with many lcd displays within 10 to 15 years. After 38 years if it is still good, means very high quality materials are used.

[@bblod4896]

@@Crazytesseract So far, mine is still good.

[@user-fg6ro]

Any signs of the lcd blackening yet?

[@bblod4896]

@@user-fg6ro Nope. It lives on my desk in a cool environment away from windows and I change out the three button cells once a year to prevent leakage.

[@Crazytesseract]

No signs of the reflective layer of the LCD fading/ darkening, after so many years? It happens quite often with many lcd displays within 10 to 15 years. After 35 years, if it is still good, means very high quality materials are used.

[@carlosviloria8239]

Interesting reviews. Now if only someone could point us to similarly useful "not-crazy-expensive-vintage" calculators...

[@mandarin1257]

Unfortunately, RPN is a feature that is seldom present in modern calculators.

[@fgg63]

I have a hp-35s, a clone of hp-15c, the Swissmicros dm15l, but is imposible obtain in Oct-2021 the casio fx-61f. Pardon for my bad English.

[@ke9tv]

I have an HP calculator app on my phone. Once you get used to RPN you never go back.

[@furzkram]

I own the HP-10C, -11C, 12C, 15C, and - for a programmer a MUST HAVE - the HP-16C. I would give NONE of them away. I also bought an HP-12C Platinum a few years ago, just out of interest. Operating it somehow has not the same feeling anymore. The HP-11C lacks a few important features in programming, registers and program steps / memory, by the way. The HP-10C has even fewer of all. The handbooks or the old models from the 80s are priceless too. If you buy one used, make sure thenhandbook is there and in good shape!

[@rubbersoul2841]

HP-15c is the best field calculator ever!

[@elpasso1592]

a very good calculator not expensive with native complex calculation and 28kb programmable is CASIO Japanese Program Functional Calculator FX-5800P-N.it has 40 constants and 128 stored formulae for engeneer

[@KainkaLabs]

I´m sure there are/were dozens if not hundreds "good" scientific calculators. But this video was about some special features you don´t find in other calculators that make them especially useful for electronics engineers: - The direct keys for electronics-related calculations in the Casio fx-61F - The unsurpassed keypad-quality (+RPN) of the better HP-calculators - The unique landscape form-factor, high-contrast LCD and 10-year+ battery-life of the HP-15C I also have a few other Casios but don´t like to work them compared to the three calculators in this video. There is a reason why people usually don´t sell their HP-15C or Casio fx-61F :-) And the HP-35s is the best compromise I know of concerning ergonomics and useability.

[@kemalnottaturk2500]

I used an HP-21 in elementary school to do SIN COS and TAN. That "DEG/RAD" really threw me.

[@julioc4978]

HP has been releasing the apps for phones now, it kind of sucks that they no longer has much interest in developing hand held calculators of this quality. Cheers

[@Centar1964]

I have a HP35s but perfer my Casio fx-991es plus C as nothing else I can find has as many features and accuracy as it does. You can't beat the price either...

[@gregaustin5533]

Craig Diamond i own both , I agree i prefer the Casio. But RPN !!! :(

[@JelckedeBoer]

Hello Roger, inspired by your video I bought a Casio fx-61f. Unfortunately the cheat sheets are missing. Would it be possible to send me a scan of yours? thanks for your great channel!

[@KainkaLabs]

Yes. Write me a reminder to [e-mail] and I will scan them next week for you.

[@MrWaalkman]

I've got a couple of original 15C's and an Anniversary Edition 15C as well as the 16C (and a bunch of other HPs, TIs, Casios, and even a Commodore), but the 15C is still my go-to calculator. And you can get the desktop version for free at hp15c.com

[@mellowtube]

the hp 11c got me through Naval Nuclear Power School.

[@mtkoslowski]

@Roger = Good day. What is your opinion of the hp 48gx for electronics engineering calculations? I have an opportunity to buy one but would really like your opinion first.

[@KainkaLabs]

I don´t have one so I can´t give you much of an advice especially because because every user has other preferences and demands. If I had one wish free it would be a calculator with the LCD and the keys from the HP 15C, the direct electrical-engineering functions of the Casio fx-61F and some additional keys for direct access to the most used mathematicl functions (without needing a SHIFT-key). You should perhaps watch the follow-up video to this video about some other CASIO calculators: kzbin.info/www/bejne/hoDTZJmDdr6podU I personally only use the mentioned pocket calculators for direct calculations at the workbench. For anything more complex I use PC-software which is simply much more powerful and easier to use than even a graphical-LCD calculator.

[@mtkoslowski]

KainkaLabs : Thank you very much for your advice and time Sir. Aren’t you up a bit late?

[@user-fg6ro]

Canヲ子月日用ヘプ十把拒巨口匕

[@fabioa.565]

I have got both hp 35s and hp33s. My only complaint is about the buttons of the keyboard. They are not reliable and resistant as like as the buttons in the old hp calculators. Many people complain about this keyboard problem. Sometimes I have to push some keyboard buttons more than necessary to get the right digit on the dislay of the calculator. I regret the old hp11-C. That one was a beautiful calculator. Are there other companies that produce RPN calculators other than HP ?

[@marcuswiren1]

Swiss Micros. Enjoy!

[@Curt_Sampson]

Yeah, I just pulled out my HP 35S after leaving it for a while and discovered that I have key issues, too. Some of the keys now "click" without actually generating the input unless you continue to push it fairly hard after you feel the click. And HP is not making it easy for me to get this fixed, either; their web site apparently believes that my serial number isn't valid, so won't let me contact the calculator support department. Sigh. I really should have just spent more and gone with the Swiss Micros DM42, which also has a generally better interface than the 35S.

[@fabioa.565]

​@@Curt_Sampson yeah the swiss micro does great RPN calculators especially DM42 and DM15L although I heard about occasional keys complaint also on these calculators, in particular keys a little bit too hard to press and not smooth as like as in the old hp models. I would like HP bring back the old calculators.

[@I967]

I have just checked eBay for Casio fx-61F. The prices are beyond ridiculous, off the charts, off the planet and 300 million light years into outer space. There is absolutely no chance any sane person would pay 250 dollars for an old calculator, with no manual, not even the cheat sheet. 50 dollars maybe yes. I would pay 30 max. I have my fx-5000f and I am fine and happy, thank you very much. And those few special "magic button calculations" of the fx-61F can be done with almost any calculator, a pencil and a piece of paper.

[@KainkaLabs]

When I bought mine it was $50. That´s the law of supply & demand :-)

[@Crazytesseract]

Get a fx-991EX or fx-5800P. Impedance calculations can be programmed into the 5800P.

[@weerobot]

The Gongs made me Jump out my Skin.....ROFL...

[@Chrls5]

All these calculators i have them all compacted in my HP49g+

[@amadonervo2001]

the hp 50g is better ( keys)

[@Chrls5]

@@amadonervo2001 yes HP50g has great keys, the click is shorter but harder and very noisy, and in the hp49g+ the clicks are taller but softer and less noisy so , i like them both really but i do like more the soft landing of the keys on my hp49g+, and i think i can overclock it better than my HP50g, but the plastic quality is better in the 50g no doubt.

[@CristiNeagu]

If you want a HP-15C but don't want to pay that much for a used unit, look into SwissMicro's DM15L.

[@KainkaLabs]

I know them, but I can´t imagine that anything beats a genuine HP voyager-series calculator concerning keypress-feeling, LCD contrast and battery lifetime.

[@CristiNeagu]

@@KainkaLabs That is quite possibly true. I wouldn't know since i owned neither. Even so, one thing the DM15L probably beats the HP-15C in is price, and it certainly beats it in availability. So i don't know if the DM15L feels anything like the original. Probably not. But if one wants an HP-15C for the functionality, the DM15L is a viable option.

[@petermikus2363]

@@KainkaLabs from what i know the dm15 has pretty good keys not hp but good the visbility si really good too apparently and the battery lifetime is about the same obly a bit shorter as it has a more powerfull microchip then the original i think

[@rlamb51]

I’ve owned a HP42S since my college days in 1992. I up graded to the HP 48 GX but I find the 42S more convenient.

[@Falcrist]

The HP 42s is the most powerful (non-graphing) scientific calculator ever mass produced (with a few POSSIBLE exceptions like the HP 41, and certain low production run calculators from smaller manufacturers). It was the last truly high-end scientific to be made before graphing calculators took over the high-end market. As such, the 48GX wasn't really an upgrade. It's only recently with the DM42 that an upgrade come out.

[@MichaelKathke]

In my opinion the 48SX was the real great follower to the 42 series. The GX was a step back in quality, keyboardlayout, documentation etc.

[@noth606]

Michael Kathke I would agree on this, I used to have a 48SX, sold it many years ago which I regret much. However I recently found a very good condition 48G which I picked up, and I can't get used to the function key setup on it. It isn't nearly as convenient as the 48SX, certainly not if you have used the 42S/48S/48SX. But I now also have a 41CV which is an awesome thing in every way except for the battery life which is abysmal, and uses non standard batteries that are difficult to find.

[@stevenpryor1114]

Hi people You can still buy HP42S calculators .. Try SwissMicros 😃

[@michaellerner6986]

@@stevenpryor1114 DM42 is an amazing calculator but it costs about GBP200.

[@eder4948]

I need to find the key (:) can you help me? Thank you

[@KainkaLabs]

What???

[@eder4948]

KainkaLabs : hp35s

[@vinicius_couto]

Que botão seria este? Já procurou no manual da calculadora?

[@TMSBRANDA]

Do you mean the Divide-Funktion? It is above the '✖️'-Key: (➗) on the HP 35s

[@user-zt8dm1oz3s]

How to make a (1/2) (1/4) in fx61F

[@KainkaLabs]

"2" --> "1/x" --> "*" --> "4" --> "1/x" --> "="

[@nixuser1980]

Any issues with the keys? Also, I've seen issues with close to limits tangent operations such as tan(89.999) giving a slightly off result. Any thoughts?

[@KainkaLabs]

No, I never had any issues with my HPs or the Casios. Any inaccuries at the limits of some functions are purely accademic in my view.

[@lenkapenka6976]

You know the DM-1x L's (such as DM-15L) have superior contrast on the LCD and with changeable fonts.... far easier to read the "heavy" block font of my DM-15L and DM-16L than the one on my HP-16C (1985 produced). In fact the 15L has 4X the memory (with latest firmware), around 50X as fast (but not as fast as 15LE) and has USB connectivity to load/save state including developing programs offline ))) all running the =original= ROM in emulation... the HP 35s contrast is useless... I rarely use the 35s nowadays.

[@hansdevreught5459]

I must say I have several SwisssMicros calculators (basically modern versions of succesful HPs). I have the DM15L (like the HP15C) and the DM15 (creditcard size version). They are the calculators I use most (yeah I've als cat the top of the line ones of HP, TI, and Casio as well). Modern calculators can do much more but they are also far more complicated to use.

[@shaunmorrissey7313]

Ti 85 for me

[@rlamb51]

Or you could get the HP 48 app for your phone or iPad for just a couple of bucks ( dollars US).

[@snake5394]

or get Free42 for free

[@emondrag]

@@snake5394 I have the m48 (also the m48+ for like $12). The m48 emulation is beyond outstanding. I can finally carry my HP48G everywhere with me. I actually got an iPhone for the only reason of having the HP48G with me at all times. It's the real deal and it looks exactly the same. Unfortunately is not on the App Store anymore. I have a quite a collection (that keeps growing) of HP calculators. The HP48G is the best. But it's a bit big. I want a 42S or something similar, like a 15C but they are very expensive on eBay.

[@snake5394]

Tthe 48g is available on android as DROID48.

[@mikemullenix6956]

What is a maker ?

[@KainkaLabs]

en.wikipedia.org/wiki/Maker_culture

[@mikemullenix6956]

@@KainkaLabs interesting. I didn't know that making was a science/art . I found your channel researching hp calculators. Had no idea of the hp15c or others you described. I own a couple of hp49g+ calculators. thankyou for the Excellent videos

[@petermikus2363]

And interesting enough out of these the casio is the most expensive.

[@KainkaLabs]

I think a genuine HP-15C is still more expensive on Ebay than the Casio fx-61F, although prices have risen exponentially for the Casio after Dave Jones and me have shown them on KZbin :-)

[@petermikus2363]

​@@KainkaLabsyou can find working HP 15C's in decent working condition for about 120-150$ i haven't been able to find an fx61 for less than 200$ lately.

[@john_hind]

Surely a smartphone app is the way to go these days? I like Mathlab Graphing Calculator.

[@KainkaLabs]

Nothing beats the ergonomics of a good standalone scientific calculator :-)

[@rickideemus]

An engineer is a "maker'?? I thought an engineer was more of a _designer._ Oh well...

[@KainkaLabs]

Every (electrical or mechanical) engineer I know personally is also a maker (or was one before university, job and family took all his time for making).

[@rickideemus]

@@KainkaLabs I guess maybe it's the translation from German. I knew a guy who headed the special tools division at Snap-On for many years. He had an engineering degree, of course, and he worked with his hands on a daily basis, but he'd never call himself a "maker"! That word is usually reserved for the ultimate "maker" in the U.S. -- i.e. God himself. Now, Gary (long retired) WORKED for the MANUFACTURER -- Snap-On Tools. They "make" many tools and machines, etc., and might occasionally be called "tool makers," but the bosses there generally come from the marketing department, and would have no use for a scientific calculator. Wouldn't know a square root from a tangent. ;-)

[@CristiNeagu]

A note on RPN and algebraic. You say that algebraic is what's used on all the other scientific calculators. That's not true. Most scientific calculators, including newer models from HP, use infix notation, and it is vastly superior to RPN. I understand why RPN is much better than standard, one operation at a time algebraic input, and i understand why so many people use it. But it seems to me like people that have adopted RPN don't even want to admit infix notation is a thing. The market doesn't seem to agree with RPN in any case. I don't think there is any calculator manufacturer that still has RPN as the default entry method today.

[@KainkaLabs]

Of course I disagree, Infix is for "dummies" and RPN is for real engineers/scientists :-) I can´t imagine a single persn who has ever converted from RPN to algebraic or infix notation.

[@CristiNeagu]

@@KainkaLabs So you do agree that infix is more efficient than RPN. Otherwise, if RPN were more efficient, i would expect the dummies to use it cause they can't use infix :)

[@Curt_Sampson]

I find RPN to be more efficient than infix notation because you don't have to type the annoying parentheses, for a start. It also makes it easier to see and re-use intermediate results. (This facility is something you may not appreciate until you start using it; I'd imagine that algebraic and infix calculator users don't miss because they never had it and so could never realize how useful it is.)

[@CristiNeagu]

@@Curt_Sampson I have had the calculator on my phone set to RPN for quite a long while now, hoping i would start seeing the benefits. So far, all it does is annoy me. I want to do 7 plus 3, but i can't cause i need to do 7 plus 3 oh wait it's RPN, so plus again. For everyday use, RPN is a headache. For more complex maths, algebraic is simply easier to read. The fact that you have fewer key presses with RPN (which you do) doesn't count for much when you have to analyze the equation you're calculating to determine where to start. RPN makes sense on scientific calculators like the HP50g, where the stack-like environment helps with programming and running programs. RPN also made sense in the days before algebraic, when some calculations were impossible to do without RPN. But these days? RPN is just like the Dvorak keyboard: more efficient, but not efficient enough to be a real option.

[@Curt_Sampson]

@@CristiNeagu If you're doing that "oh wait" thing you are _really_ not used to RPN at all. I have the exact opposite "oh wait" problem on algebraic calculators. Nor is the "analysis" of the equation an issue once you're comfortable with RPN; it's the same "analysis" you already learned to do a a child and do when calculating the result of simple equations in your head. (I don't think that anybody finds it difficult to work out the answer to 3+4*5+1 without recourse to a calculator that can understand the order in which you do the additions and multiplication.) It's automatic once you're comfortable with RPN. It sounds to me as if you're still stuck having the standard problems of someone well familiar with algebraic input and unpracticed with RPN. That's not a fair basis for comparison, though it's certainly reasonable for you to claim that _in your personal situation_, and given your background, it's not worth the effort for you to learn. I'm not sure where "easy to read" comes in, either; who types in an equation on a calculator and then reads it back? Well, I guess you might need to in algebraic/infix mode to make sure you've typed in the parentheses properly, but that step is completely skipped when you're using RPN. (BTW, it's strongly disputed that the Dvorak keyboard is even marginally more efficient than QWERTY. It may well be slightly better where you start _ab nihilo_ with both systems, but it seems to take very little investment in one standard to make it not worth switching to the other.)

[@stevenbliss989]

Yep HP-35S is GREAT! ...But INSANELY priced, when HP still sold them. Now used still crazy price! :( The newer CASIO Fx-981EX on the other hand is GRAT VALUE! ...even though they F...ED up the u m k etc. is now a three button sequence , ....MORONS!!!!!!!!!!!! :(