SwissMicros DM42 - Advanced Scientific Programmable Calculator with High-Resolution Display and Metal Case

I have a small collection of calculators, but this is now the one I now use all the time. When I was a student way back in the 1970s, I really wanted an HP-65 – HP's original magnetic card programmable – but I could never afford it. This does everything the HP-65 could do and the ability to transfer programs to and from a PC replaces the limited magnetic card storage. Plus there is a much bigger display with graphic capability, and the standard 4 entry stack can be extended into the much lager memory. This allows you to interrupt one calculation, perform a different one, and then resume the original without fear of running out of stack space.For more complex programs, it can be a little tedious to enter them a keystroke at a time, but I found a compiler on GitHub which can translate programs written in a simple high-level language into keystrokes – particularly useful with matrix calculations. An emulator is also available that allows programs to be tested on a PC before uploading them to the DM42.

I'm fair when it comes to writing reviews and like to think I give the good and the bad. I bought this calculator as a modern take on the HP-42s calculator and have nothing but praise for it. I have since bought a HP-42s and have compared the two. I prefer the HP clickier buttons but the DM42 isn't far behind and they do the job well. Other than that, the DM42 is far superior in lots of ways - better screen resolution, more display lines, adjustable font size, load and save programs, dedicated top-row function keys to name just a few. They both have RPN keystroke programmability which is the main reason I bought them.The only improvement I could think of is to have a backlight for when it's getting dark but that's not a criticism.If you like/want to try RPN plus writing your own programs on a modern version of the HP-42s then look no further and buy this. It's really that good.

If you like RPN calculators then this is the best there is. Powerful but simple programming, easy to use, great battery life, incredible multiline screen, everything a scientific calculator should be. I use it daily for engineering and statistics. It has a quality feel and should give many years of service. Compatible with HP 42S and HP 41C series calculators means that there are plenty of programs available if you don't want to write your own. Can connect to your computer to transfer the programs and backup the calculator. Too many features to name.

Shape, keyboard feeling, and programming features, along with its unique calculating performance and its ability to communicate with a PC through its USB port as well, for programs' storage and firmware updates, make this unit a real winner.

One of the very best calculators there is. Expensive but worth it. Amazing build quality and features.

The DM42 is by far my favourite calculator to use. It successfully manages to combine the huge number of functions of a scientific calculator with the simplicity and elegance of a RPN pocket calculator, all on top of being the most customisable I've ever owned. The CUSTOM menu and XEQ make the calculator significantly extensible and easier to use if you have a specialised use case and having save states like a computer emulator makes filling memory (annoyingly easy to do on my casio graphing calculator) a complete non-issue! And even if you filled the calculator with states, you can offload them onto a computer, but I don't see anyone ever having a genuine need to do that.Unfortunately the calculator loses three stars for its build quality. The printing of the shift key legends on my calculator is noticeably off-angle (see picture), which is very disappointing for such an expensive device. I normally would not nitpick about such things, but since the calculator costs well over £100, I can't really overlook this and it's something that you should think about if you're considering buying this calculator.

Most precisely than original and it is 10000 times faster!

I own a few HP calculators and when I originally saw some videos on YouTube of the DM42, I wasn't too sure, but I should not have doubted. This is a tremendous calculator. If you are familiar with the HP-42s, this is a turbo charged version of it. If you are not familiar with the HP-42s, it is possibly one of the best calculators ever made, and this is a superb remake of it.There is not really much I do not like about it. It does everything you would expect it to do very well. It is fast, there is loads of memory, it is as easy to use as the HP-42s was, it has a great screen, much bigger than the original, which means much easier debugging of your programs and you can see all registers at once.Only thing I would have suggested is to put "F1" to "F6" on the additional row of buttons for easier referral. I would also have suggested printing the letter labels on the keys in a different colour for better contrast. The other very minor niggly bit is that if you fully press the ENTER key you get two clicks. This does not affect the number of times ENTER is actually pressed, but it feels a bit "odd".I especially like the built quality, which you can't really see on the pictures. This is a very well made product. An all metal body with quite a weight to it. Feels like it can handle a lot of abuse.The PC connectivity is a great addition, it allows you to save your programs and states to your PC for backup purposes, or indeed easily share programs.The screen is very clear and high contrast, which is great when your eyesight is not so good (like mine). The fact that it is nice and large really helps with programming. You can change the font size to see up to 10 lines of code (a bit too small for me). At 8 lines of code it is nice and crisp and easy to read.If you need to do some serious calculations for engineering or science purposes, this really is a superb calculator that will not disappoint. Well done SwissMicros.