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HP 35s/RPN replacement

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AZsurvyor
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I found out sometime last year that the HP 35s, seemingly the last of its kind, was discontinued a few years ago.

I have a few that are over 15 years old and still work well, though one has started to stick when pressing the buttons.  I haven't opened to perform a basic cleaning but when I looked for a replacement (figured it wouldn't hurt to grab a few more to keep in inventory), I learned the disheartening news. 

It appears that HP does not have anything on the horizon as far as RPN format as concerned and upong looking at some alternatives, there is really nothing that is taking its replacement.

You can find some used 35s on eBay, but they come with a hefty price tag, and while there appears to be a European version, the price tag is outrageous quite literally.

I know of a company in Florida that repairs old HP 48s, and while I’ve had a few fixed before, due to lack of use, they're out of commission once again.  I'm sure it's just simple cleaning of the contacts. 

So what’s everyone doing for RPN calculators these days?

Going digital seems to be the trend, but honestly, like restaurant menus, nothing beats the traditional feel, even with how much we rely on our phones now.


 
Posted : January 5, 2026 2:07 pm
bill93
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I found an RPN app for my phone. Key layout isn't optimum, but the functionality is there. There may be others.

As a plus, the app shows the stack contents, which my 15C from 1979 doesn't. But my two 15C still work fine, among very few pieces of old electronics that still do.


 
Posted : January 5, 2026 2:48 pm
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AZsurvyor
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I have a few that I have been using in my phone for a number of years now but when I am at my desk, I always reach for the traditional calculator. 

 

Just one of those habits that humans can't seem to do away with.   


 
Posted : January 5, 2026 6:40 pm
jhframe
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Take a look at Swiss Micro.  They have some modernized HP-like models that look pretty good.


 
Posted : January 5, 2026 7:50 pm
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john-hamilton
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I really loved my HP41CX. I used that for many years before PC's, and wrote a lot of programs. Astro, state plane, UTM, data collection with a T2, plane table reductions, and a lot of others. One was to collect leveling data for a 130 mile bluebook run we did in the 80's. Manual readings with a level (micrometer double scale and three wire) but after that it was all automated, checked the data for each setup, and in the office I had a program to format for NGS specs. Saved a ton of time in the field and office

I had the HP survey card for it, ran and computed a lot of traverses with it. Also a 300 baud modem, HPIL loop to download, printer, cassette drive, card reader, etc. A guy I worked with in Virginia had written a least squares program for the HP97. 

I later bought a 48GX, never liked it as much as the 41CX. My 41CX is dead, and the 48GX I think still works but I don't use it. I now have a 33s on my desk just for normal calculator stuff. And a Swiss Micro DM41L. 

To this day I cannot use a calculator with an = sign on it!

 


 
Posted : January 6, 2026 10:13 am
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AZsurvyor
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Swiss is quite proud of their (HP) design if they want $500 for a RPN calculator.  


 
Posted : January 7, 2026 1:20 pm
john-putnam
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The 41x lists for 259 Swiss Franc which is around $290 US.


 
Posted : January 7, 2026 3:48 pm
Norman_Oklahoma
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Posted by: @john-putnam

The 41x lists for 259 Swiss Franc which is around $290 US.

It's being sold on Amazon for $439.  So I wonder about the tariff situation. 


 
Posted : January 7, 2026 4:36 pm
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AZsurvyor
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At that rate, I could land a new HP35 from ebay, which I am already familiar with.  


 
Posted : January 15, 2026 9:16 pm
bernardc
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The HP 41CV emulator on my iPhone works great.


 
Posted : January 16, 2026 12:16 am
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