Plus42

Don’t waste your money!

Once you use an RPN calculator, you will never go back. The HP-42S beats the HP Prime in layout and ease of use for most task, and the enhancements in this implementation is great. I love having the (enhanced) HP-42S always with me on my iPhone whenever I need a calculator.

I’ve really like this calculator however lately there seems to be an issue with programming. I had a program for the sulfur to convert Celsius to Fahrenheit and vice versa but for some reason it doesn’t work anymore so 212 Fahrenheit should be 100 Celsius. it comes up with something like minus one point something to the power of 6000 I wonder what the issue is?

The 42s was, in my opinion, the most elegant calculator ever devised during the golden age of HP engineering. This simulator perfectly recreates this legendary calculator and it adds some additional great features. It has several enhancements seen in the RPL calculators without introducing the shortcomings of the more complex interface. Put another way, this calculator is what HP should have done with the 48 line. I believe that Plus42 now deserves the crown of the best calculator. It is the perfect continuation of the RPN days, and since it lives on your phone, it is always at hand. All that for just under $10!

Can’t believe how happy this app makes me, to once again have my favorite calculator in hand. The HP-42S was unmatched and this app replicates it perfectly. Simply amazing. Thank you!

I can’t believe I missed Thomas Okken’s free42 and plus42 projects until now, over 20 years after his first release it appears. It’s been a joy to get reacquainted with RPN and now have the same calculator on my phone, which I have on me all the time, as I have at my desk in physical form via SwissMicros’ DM42n that just arrived. Having a physical calculator at my fingertips that I love to use is something I haven’t experienced in probably 30 years, since college. The astro navigation and conversion apps I pulled down and loaded from Thomas’ website this morning is what prompted me to write this review. Thank you Thomas for this gift to us all! You’ve left no detail out for someone like me.

I tried several calculators apps and in my opinion this one is the best by far. It has much more than I need and yet it is easy to use and intuitive. This is the one I use most.

In college I was an HP41C user. Once in my first engineering job I switched to the HP42S which has served me well over my 30+ year career. Once iPhones became a thing, I loaded Thomas’s Free42 and have been using that for a couple decades. I still have a real 42S on my desk for daily use. I recently purchased an HP Prime which is a lovely calculator but it’s just not completely comfortable to use. Switching to Thomas’s Plus42 feels really comfortable and adds lots of lovely features. I will likely purchase a SwissMicro DM42 to be used as my daily desk calc so that my phone app and physical desk calc are similar. That would send the 42S to the vintage calc cabinet. Honestly having this on my phone is massively so functional it’s hard to justify even owning a physical calc but there are times at the desk when it’s nice to grab the physical unit with tactile keys that can’t be interrupted with alerts :-). This is a beautiful upgrade to the free42. Thanks Thomas!

When using on iPad, the app occupies the whole screen. Currently it does not support multitasking. But it would great to share the screen with other apps (side or floating window).

Thomas has done an outstanding job on this app! It is not only the most beautiful calculator app out there, but it’s also the most powerful and functional of any of the HP inspired calculator app. The graphics are outstanding and the “extras” that were added in addition to the 42s standard makes the app even more appealing. If you know how to use a RPN calculator, this IS the one to have and use. If you don’t know how to use a RPN calculator, learn how and buy this. I always carry my phone, but rarely my physical DM42 or “real” 42s. You won’t regret getting this app. Congratulations Thomas for all the work you have done over the years relating to the 42. You should be proud.