Plus42 vs my12c
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
- 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
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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.
my12c
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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
Verdict
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
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.
Plus42 ships an update weekly, my12c every 3 days. The most recent releases landed on October 22, 2026 and October 13, 2026 respectively.
| Parameter | Plus42 | my12c |
|---|---|---|
| Price | $9.99 | Free — better |
| Rating | 4.9 (79 ratings) — better | — |
| Positive reviews | 92.3% of reviews | — |
| Number of ratings | 79 — better | — |
| Update frequency | Weekly | Every 3 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Mac |
| Requires iOS | 15.0 — better | 26.0 |
| Further details — not scored | ||
| Size | 11 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | Thomas Okken | Miroslav Perovic |
In-app purchases
Plus42
No in-app purchases
my12c
- Unlock Full App$9.99









