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The SwissMicros Company


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We are a small manufacturer of RPN calculators based in Switzerland.

Company Address

SwissMicros GmbH
Seestrasse 149
8712 Stäfa
Switzerland CH

Tel. +41 79 431 7177

Company Registration

HRA Zürich CHE-470.007.328

Contact us



Michael Steinmann

Emy Amstein


Barbara Pulli


Date History
Jan 2011 Michael discovers David’s prototype of an HP-15C clone based on a PIC processor and a Nokia LCD.
Jul 2011 First pre-orders placed on
Feb 2012 First batch of DM15 being shipped out
Jul 2012 Second batch being shipped out
Aug 2012 Listed on Wikipedia under Hewlett-Packard_Voyager_series
Nov 2012 Silver Edition calculators released
Dec 2014 SwissMicros GmbH company registration
Aug 2015 DM15L release
Dec 2015 DM41L and DM16L release
Feb 2016 DM42L prototype complete
May 2017 DM42 release
Sep 2020 DM41X release
Sep 2020 New website and branding
May 2021 Update


  • "Mathematics is the language that we humans are capable of using [to] describe the Universe. It may have little to do with the Universe but, in terms of our capacity, it's the microscope, it's the telescope […] — it's the lens through which we are able to view the Universe with a precision which no other human language allows."
    (Jim Gates, Lex Fridman podcast #60, Dec. 25th, 2019)
  • "When you pay too much, you lose a little money – that is all. When you pay too little, you sometimes lose everything, because the thing you bought was incapable of doing the thing it was bought to do. The common law of business balance prohibits paying a little and getting a lot – it can't be done. If you deal with the lowest bidder, it is well to add something for the risk you run, and if you do that you will have enough to pay for something better."
    (attributed to John Ruskin, early 20th-century)
  • "Some people say you have to be a little crazy to buy an RPN calculator. Well, in that craziness we see genius and that's who we make the world's greatest programmable RPN calculators ever for."
    (inspired by Steve Job's Think Different claims, 1980s)
  • "It isn’t equipment that wins the battles; it is the quality and the determination of the people fighting for a cause in which they believe."
    (Gene Kranz, Failure is not an option, 2011)

What Customers Say

I am very happy with the DM42: it is very well built, of great quality: it has a nice metal case, an excellent keyboard, a high-quality display and could be repaired if necessary (as the case can be opened). The software is very stable and offers the "dynamic stack extension" (convenient for HP48 users). I am very happy that there is still a manufacturer of RPN calculators: I think RPN is superior to other entry methods as it teaches students the structure of mathematical expressions (and is a very natural way of turning a complex mathematical expression into a tree of operations). This is an excellent product and it is a pleasure to work with it!

July 9, 2024
Zurich, Switzerland
Yves Acremann

Have I written you lately to tell you how much I love the DM41X!! I seriously use it every day in my work and keep one at the office, one at home, and one in my computer case. It has surpassed my 41CX with a NOV64 and my 41CLs as my favorite and go to calculator. No other HP I own even comes close…

April 29, 2021
Salt Lake City, UT USA
David M. Ingebretsen, M.S., M.E.

I'm a user of the DM42 and I love this RPN calculator. It's the best calculator I've ever held in my hand. It represents what can be done with a pocket calculator - Engineering at its best and high-quality workmanship.

This quality, in addition to innovativeness, dwarfs everything else in the field of concepts of pocket calculators - better than HP-42S.

December 13, 2020
Finnentrop, Germany
Dr. Franz-Josef Bock

I received the DM42 yesterday. Nine days from order to delivery from Switzerland
to Michigan; that is exceptional. I had very high expectations for this calculator
and I can tell you from my initial impressions that you have exceeded them all.
I look forward to many years of enjoyment from it.
Thank you for producing such a high quality product — a rarity with today’s throwaway mentality.

August 21, 2020
Ferris State University, MI USA
Dr. Clifton Franklund

I received the DM42 last week and I'd have to say this
will go down as the world's last truly great calculator.
It is an unbelievably brilliant piece of technology and engineering that is a pleasure to use.
After some 40 years in engineering I have seen nothing that is even close.

August 3, 2020
Perth, Australia
Dave Nesbit

Only one word can describe your DM42 calculator: WOW
The HP42 calculator was my absolute favorite calculator of all time - I've used one since high school and the RPN cannot be beat.
I casually joke with my students that it's "the best calculator ever made by man or beast".
With your DM42, you've managed to outshine HP.
I don't think that I've ever been this excited for any gadget, especially a calculator.
To produce this work of art must have taken a colossal amount of effort, so my sincere thanks to you and your team for bringing this calculator to life.
It truly is a marvel of engineering and is everything that I have ever wanted from a calculator!
Thank you so much!

November 4, 2019
Embry-Riddle Aeronautical University, USA
Akhan Almagambetov

Wow! got my DM11L today. Absolutely beautiful.
Keys feel like my original 11c from the 1980s.
Performance is blazingly fast.
This must have been a huge amount of work.
You deserve a place in calculator heaven. Bravo!

July 27, 2019
Norwalk, California, USA
Lex W. Rooker

I would like to thank you and your team for this outstanding and truly beautiful product.
I can not even begin to imagine how much passion you must have invested in its design and production.
I hope HP have ordered one as an inspiration for their future mass market calculators.

March 26, 2019
St-Cergue, Switzerland
Marius Lohri

I received my calculator today, and it is one of the most robust electronic devices I have ever held.
It's nice to know that there are still people out there who refuse to shirk on workmanship.

December 12, 2018
Brampton, Canada
Brendan Toles

Just had to write to say thank you for the DM42s which arrived very quickly here in the UK.
I have been using it for a few days now and I must say I am so impressed.
The display is really crisp and clear, the keys feel great and the overall build quality is everything I was hoping for.
It is a credit to you.

September 20, 2018
Bury, UK
Peter Butterworth

Yesterday DM16L arrived. I use it pleasantly.
Thank you for your prompt and courteous responses.
Your company is very wonderful. Thank you very much for this time.
I wish you health and continued success. I pray for the further development of your company.

August 16, 2018
Takashi Matsumoto

I have just received the DM42, quality and functional expectations was high, but here we are facing a masterpiece!
Thank you so much.

July 28, 2018
Tarzo, Italy
Roberto Balbinot

I haven't been this excited about a calculator since I first learned how to program on an HP 67 back in 1976.
It's been almost 20 years since HP put their name on a quality Advanced Scientific Programmable RPN Calculator
and nobody else has either until now. Despite being a small company, David and Michael have demonstrated their dedication to improving
quality until they've produced a product that's comparable to the best that HP ever made.
The DM 42 calculator is 450 times faster than the HP 42s, calculates with 34 digits, displays 10 lines of code, has 10 times as much
memory, has its own USB drive, and Programs and Matrices can be sent back and forth to a computer via a USB cable.
It looks and feels great, and in the weeks that I've had one, I've known it to be reliable and durable.
The convenience of Bill Hewlett's shirt pocket sized numerical tool can't be over stated:
It's just as important today to scientific professionals, students and teachers as it ever was, and I still believe it's the best way to learn how to program.

March 3, 2018
Jim Crepps

The DM42 just arrived. It is awesome! The build quality is outstanding, and the display is the best I've seen on a calculator.
You may have outdone yourself, building better HP calculators than HP could.

February 13, 2018
Knoxville Tennessee, USA
John Sonewald

I am extremely satisfied with the looks and the build of the DM42.
It is another step up in quality and craftmanship compared with the DM15 and the DM41L that I acquired earlier.
The screen, the keyboard, the outlook and the heft of the calculator exude quality.
HP-like quality. Eighties-HP-like quality, to be more specific. This HP-42s reincarnation is a thing to behold in its own right.
The screen is vastly superior and of course the speed, the memory size and the numerical precision are also much better.
The connectivity that was notably missing on the HP-42s has now been restored.
You gave us a terrific physical incarnation of Thomas’ terrific simulator – and more.
Just to say that I am really grateful for this very nice piece of Swiss craftmanship.

January 8, 2018
Leuven, Belgium
Jeroen Van Nieuwenhove

Thank you for creating the DM42. It is very high quality, feels great in the hand, and is superior to the HP-42S in every way.
I was initially a little concerned about paying $200 for this calculator, but now that I have it in hand it's clearly worth every cent.

Mountain View CA, USA
Chris Hanson (Software Engineer, Google)

Press Releases

Terms and Conditions

General Terms and Conditions of SwissMicros GmbH.

  • Conditions - Offers, Services and Sales of SwissMicros are made only pursuant to these conditions.
  • Prices are subject to change without notice.
  • Prices exclude Taxes and duties.
  • Orders may be rejected for any reason. Prepayments made by Customer will be refunded in this case.
  • Inventory is subject to prior sale.
  • Warranty period is five years unless otherwise noted. At its discretion, SwissMicros may repair the product, replace it with an equivalent new or refurbished product, or refund the purchase price.
  • Liability - SwissMicros shall not be liable for any sum greater than the amount paid to it for the goods or services sold, in the event of any loss, cost or damage caused by, arising out of, or related to, the goods or services rendered. Customer's sole and exclusive remedy in the event of an error or defect is limited to the correction of the error or defect by adjustment, replacement, or repair, at SwissMicros election. In no event shall SwissMicros be liable for direct, indirect, incidental or consequential damages, including lost profits and loss of data.
  • Ownership - Goods and services supplied remain the property of SwissMicros until paid in full.
  • Payment terms - payment is due before delivery. For qualified customers, payment is due without deduction within 10 days.
  • Returned shipments - For shipments returned by the post office / courier service, refund or credit is given with round trip shipping / import fees deducted.
  • Legal venue is Zürich, Switzerland, using Swiss laws.


SwissMicros FIVE (5) YEARS Limited Warranty.

What is covered by this warranty?

SwissMicros warrants the SwissMicros branded hardware product and accessories against defects in materials and workmanship when used normally for a period of FIVE (5) YEARS from the date of original retail purchase by the end-user purchaser ("Warranty Period"). If you sell your SwissMicros branded hardware product or give it as a gift, the warranty is automatically transferred to the new owner and remains in effect for the original FIVE (5) YEARS Limited Warranty period.

What is not covered by this warranty?

This warranty does not apply:

  • to cosmetic damage, including but not limited to scratches and dents
  • to damage caused by accident, abuse, misuse, liquid contact, fire, earthquake or other external cause
  • to defects caused by normal wear and tear or otherwise due to the normal aging of the SwissMicros Product

If during the Warranty Period you submit a valid claim to SwissMicros, SwissMicros will, at its discretion, repair or replace the SwissMicros Product.

Return Shipping Options

  • Do not send us anything without letting us know in advance.
  • For customers in any location, you have the option of using the carrier of your choice to return your order to us.
  • All shipments must be made prepaid; packages shipped COD will be rejected.
  • International shipments should be marked as a "Merchandise Return".

Postal shipments require a CN22 customs label (available at your post office) on the outside of the package. Please declare as "electronic parts, defective" with a low, but NON-ZERO value (e.g. USD 10). We have to pay customs handling fees for shipments with a value over ~ USD 20 / EUR 15.
IMPORTANT: Declare a low value to avoid import taxes, otherwise we will refuse the parcel.

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