Plus42

🇺🇸 United States
Thomas Okken  | 
43
ASO score
Text
37/100
Reviews
50/100
Graphic
60/100
Other
0/100
rating
App Rating
4.9
rating
Votes
192
rating
App Age
3y 8m
rating
Last Update
Oct 29, 2025

Compare with Category Top Apps

Metrics
Current App
Category Top Average
Difference
Rating
4.9
4.47
+10%
Number of Ratings (Voted)
190
743.2K
-100%
App Age
3y 7m
6y 6m
-45%
Price
$10
$0
In-app Purchases Price
$0
$39
Update Frequency
72d
43d
+67%
Title Length
6
25
-76%
Subtitle Length
30
27
+11%
Description Length
847
2 666
-68%
Number of Screenshots
1404
1020
+38 %
Size
11MB
169MB
-93 %

Category Ranking in United States

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Ranking Keywords in United States

Keywords App Rank
Illustration
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Text ASO

Title (
Characters: 6 of 30
)
Plus42
Subtitle (
Characters: 30 of 30
)
Enhanced HP-42S Calc Simulator
Description (
Characters: 847 of 4000
)
Plus42 is an advanced scientific programmable calculator, based on Free42. Free42, in turn, is a complete re-implementation of the HP-42S scientific programmable RPN calculator, which was made from 1988 until 1995 by Hewlett-Packard. Free42 is a complete rewrite and contains no HP code whatsoever. Plus42 builds on Free42 and adds: Algebraic expressions modeled after those used on the HP-27S and HP-17B/19B; attached units and unit conversions modeled after those used on the HP-48/49/50 series; directories for more organized storage of programs and variables; a larger display, with 8 rows and 22 columns (131x64 pixels) by default, which the user may resize at will; time value of money and amortization schedules; and two-dimensional plotting of functions, with ability to zoom and pan, and find integrals and roots from points in the plot.}
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Visual ASO

Screenshots

Rating & Reviews

Reviews Overview
🧐 Coming Soon…
Rating
4.9
192 voters

Some Latest Reviews

Salted12345
01 Oct, 2025
5
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!
HaraldiC
08 Jun, 2025
5
Ich nutze den Rechner jetzt schon seit längerem (in der Plus-Version). Bin sehr begeistert, echt super!!! Auch das Programmieren funktioniert „wie gewohnt“ (wie früher), echt cool, danke!
orivaa
14 May, 2025
5
If you know you know. This calculator is the best on iOS. It not only keeps everything about the HP42 but enhances it nicely. I have it as an action button shortcut.
Jib Sheet
28 Feb, 2025
5
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.
DonderDassie
05 Nov, 2024
5
Great implementation of the HP42. Would love it if the developer could add a dark mode icon.
Supong
31 Aug, 2024
5
Excellent programmable scoentific RPN calculator. Please make more sharp skins and adjustable result screen brightness.
Barabasz
14 Jul, 2024
5
This is simply the best calculator in Appstore, second to none. Outstanding usability, great user interface - I love to use it even when I don't have to :) great job Thomas Okker!
Bill Graves - Tampa
06 Jul, 2024
5
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!
Paul Mina
08 Apr, 2024
5
Happy to support the dev as the desktop version was free.

Other

Additional Information
Rating:
4.91
Voted: 192
App Store Link:
Price: 9.99 $
Website:
Email: -
Privacy Policy:
Categories: Utilities
Size: 11MB
App Age: 3 years 8 months
Release Date: Apr 28, 2022
Last Update: Oct 29, 2025
Version: 1.3.12
Version history
1.3.12
Oct 29, 2025
Fixed crash in menu logic.
1.3.11
Oct 16, 2025
Fixed crash in EQN->R/S when EQNS does not yet exist. When a new program was created by inserting END, the new program could end up being locked initially. Fixed.

More by Thomas Okken

Version history