Comparison

Plus42 vs my12c

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Plus42

This advanced scientific calculator simulates the classic HP-42S RPN calculator with enhanced features. It offers algebraic expressions, unit conversions, directories for storage, a larger resizable display, financial functions, and 2D plotting with integral and root finding.

Highlights
  • HP-42S RPN calculator simulation
  • Algebraic expressions
  • Attached units and conversions
  • Program and variable directories
  • Resizable 8-row, 22-column display
  • Time value of money and amortization
  • 2D function plotting with zoom and pan
Features
Read full description

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.

About

my12c

Read full description

The financial calculator that has been on every banker's, broker's and realtor's desk since 1981 — now on your iPhone, iPad and Mac. my12C brings the legendary 12C Voyager series financial calculator back to life with cycle-accurate emulation running the original microcode. Every keystroke, every display flicker, every RPN operation — faithfully reproduced. WHY THE 12C NEVER WENT AWAY The 12C is the longest-lived calculator ever made, and for good reason: its time-value-of-money keys, cash-flow analysis and RPN logic solve real financial problems in a handful of keystrokes. It is still the calculator used in finance courses and licensing exams around the world. FEATURES • Cycle-accurate emulation — runs the original Voyager microcode, not a simulation • Time value of money — n, i, PV, PMT and FV, solve for any of the five • Amortization — interest and principal for any range of payments • Cash-flow analysis — NPV and IRR for up to 20 grouped cash flows • Bonds — price and yield to maturity on the 30/360 basis • Depreciation — straight-line, sum-of-the-years-digits and declining-balance • Calendar — days between dates and date arithmetic, actual and 30/360 • Percentages, simple interest, odd-period compounding, statistics and linear regression • Programmable — up to 99 lines, with conditional tests, branching and looping • RPN entry — the efficient Reverse Polish Notation four-level stack • Authentic 7-segment LCD display with all original annunciators • Built-in self-tests, working exactly as on the original hardware BUILT FOR TODAY • Complete Owner's Manual inside the app — every section, worked example, cash-flow diagram, formula and program listing of the original handbook, with a linked subject index • iCloud sync — your calculator state follows you across devices • Native on iPhone and Mac — landscape optimized on iOS, resizable window on macOS • Full keyboard support on Mac — type numbers and operators directly, Enter on the numeric keypad works as ENTER • Dark interface faithful to the original Voyager design

Screenshots

Plus424 screens
my12c3 screens

Verdict

The call

The clearest difference is price: my12c at Free against Plus42's $9.99. my12c also leads on update cadence (every 3 days vs weekly). Plus42's advantage is in-app purchases (none vs 1) and iOS requirement (15.0 vs 26.0). On ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

my12c is free to download; Plus42 costs $9.99 up front. my12c sells 1 one-off in-app purchase. Plus42 asks for nothing beyond the download.

UpkeepUpdate frequency

Plus42 ships an update weekly, my12c every 3 days. The most recent releases landed on October 22, 2026 and October 13, 2026 respectively.

Scorecard4 real differences · 6 level
Plus42 versus my12c: the parameters behind the verdict, then further details
ParameterPlus42my12c
Price$9.99Free — better
Rating4.9 (79 ratings) — better—
Positive reviews92.3% of reviews—
Number of ratings79 — better—
Update frequencyWeeklyEvery 3 days — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree—
DevicesiPhone, iPad, iPodiPhone, iPad, Mac
Requires iOS15.0 — better26.0
Further details — not scored
Size11 MB6 MB
Age rating4+4+
DeveloperThomas OkkenMiroslav Perovic

In-app purchases

None

Plus42

No in-app purchases

1 purchases

my12c

One-time1
  • Unlock Full App$9.99

Questions

Is Plus42 free?
Plus42 costs $9.99, with no in-app purchases.
Is my12c free?
my12c is free to download, with in-app purchases available.
Do Plus42 or my12c have ads?
Neither Plus42 nor my12c shows ads.
Which is updated more often, Plus42 or my12c?
Plus42 ships an update weekly, and my12c every 3 days. Most recently, Plus42 was updated on October 22, 2026 and my12c on October 13, 2026.

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