Comparison

Plus42 vs RLM

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
Currently charting
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

RLM

This app is a scientific and programmable calculator designed for science and engineering, replicating the functionality of the HP-11C. It offers extensive features for finance, business, statistics, complex numbers, and unit conversions, with a programmable interface for custom calculations.

Highlights
  • Finance calculations (amortization, bond price, Black-Scholes)
  • Business functions (break-even, currency exchange)
  • Statistical analysis (regression, probability distributions)
  • Scientific functions (complex numbers, logarithms, trigonometry)
  • Unit and currency conversions
  • Programmable interface for custom scripts
  • Equation solver
Features
Read full description

The RLM-11C+ application is a general purpose calculator with a special focus science and engineering. It is based in the Hewlett-Packard HP-11C calculator, but specially designed to bring up the most of your iOS devices and , at the same time, conserving the easy of use and all functions originally provided by the real calculator. >Finance Menu: •Account Balance: Credit line type account based on cash transactions and interest rates applied. •Amortization: Loan Amortization Schedule for a single loan payment or from several payments at once. •Bond Price & Yield: Bonds calculations in an easy way with all options and values at sight. •Black-Scholes Options: CALL, PUT and “Greeks” calculations of the Black-Scholes European option valuation model. •Equal Periods: Calculations with Cash Flows occurring at regular time intervals. •Unequal Periods: Calculations with Cash Flows occurring at arbitrary dates. •Depreciation: Calculates depreciation with SL, SOYD, DB or MACRS methods and conventions. values at sight. •Interest Conversion: Nominal and effective interest conversion. •Time Value of Money: Compound Interest problems involving money earning interest over a period of time. >Business Menu: •Bill-Tip-Split: Calculates the sharing of a Bill with Tip. •Break-Even: Analyze the following relation: Profit = (Price - Var.Cost) • Units - Fix.Cost •Currency Exchange with on-line rates. •Percents & Margins: Calculates %Change, %Total and Business margins. Date / Time Menu: Calculates Date and Time intervals with all values at sight. >Statistics Menu: •One-Variable Statistics: Calculations for one variable data samples. •Two-Variable Statistics: Calculations for two variables data samples. •Curve Fitting: 6 Regression models to fit a curve based on two variables data samples. •Probability: Combinations, permutations, Normal, Exponential, t-Student and Weibull probability distributions. >Scientific Menu: •Complex Numbers: Operations and functions with complex numbers. •Logarithms, Trigonometric, Hyperbolic and Number Alteration functions. •Triangle Solution: Solves a Plane & Spherical triangles. •3D Vectors: Operations and functions with vectors in Cartesian, Spherical or Cylindrical coordinates. •Universal Constants: All the NIST-CODATA physical constants values and descriptions. •Units Conversion: Physical units conversion completely customizable. >Convert Menu: •Angles & Polar: Convert angles between DEG,RAD,GRAD,DMS or Slope % & Polar-Rectangular coordinates. •Currencies: world currencies conversions with manual input or on-line current rates. •Interest Rates: Nominal and effective interest conversion. •Units: Physical units conversions. >Program Menu: Create, edit or load previously saved programs. >Solver Menu: Solve arbitrary algebraic equations entered and saved in the equation editor and creates a menu with all the variables to solve any of them. >Utilities Menu: •General Settings: Customize the calculator to your preference. •Storage Registers: Store and perform operations directly over the calculator’s storage registers. •Memory Content: Shows all memory content edit, backup or restore. •Help Documents: learn by example about all menus. >Editors: submenu to select data editors. System requirements: iOS 15.0 or above. 30 days Free-Trial. In-App-Purchase: One-Payment for life. License Agreement: http://www.apple.com/legal/itunes/appstore/dev/stdeula Disclaimer: THIS IS NOT A HEWLETT PACKARD CALCULATOR, AND IS NOT SPONSORED IN ANYWAY BY HEWLETT PACKARD OR ANY OF ITS SUBSIDIARIES.

Screenshots

Plus424 screens
RLM4 screens

Verdict

The call

The clearest difference is price: RLM at Free against Plus42's $9.99. Plus42's advantage is rating (4.9 vs 3.1) and in-app purchases (none vs 4). 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

RLM is free to download; Plus42 costs $9.99 up front. RLM sells 4 in-app purchases, starting at $0.49 per month. Plus42 asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Plus42 holds the better App Store score, 4.9 against 3.1. That said, the two scores are not equally well evidenced: Plus42 has 79 ratings behind it against 7, so its average is the more settled of the two. Written reviews point the same way: 92% of Plus42's written reviews are positive against 67% of RLM's.

UpkeepUpdate frequency

Plus42 ships an update weekly, RLM every 5 weeks. The most recent releases landed on September 22, 2026 and September 10, 2026 respectively.

Scorecard9 real differences · 2 level
Plus42 versus RLM: the parameters behind the verdict, then further details
ParameterPlus42RLM
Price$9.99Free — better
Rating4.9 (79 ratings) — better3.1 (7 ratings)
Positive reviews92.3% of reviews — better66.7% of reviews
Number of ratings79 — better7
Update frequencyWeekly — betterEvery 5 weeks
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
Best chart rank#110 — better—
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS12.0 — better15.0
Further details — not scored
Size11 MB6 MB
Age rating4+4+
DeveloperThomas OkkenR.L.M. Software

Customer experience

Plus42

All ratings79 ratings
Positive97.5%
Neutral0.0%
Negative2.5%
Written reviews39 reviews
Positive92.3%
Neutral2.6%
Negative5.1%

RLM

All ratings7 ratings
Positive42.9%
Neutral14.3%
Negative42.9%
Written reviews3 reviews
Positive66.7%
Neutral0.0%
Negative33.3%

In-app purchases

None

Plus42

No in-app purchases

4 purchases

RLM

Subscriptions3
  • Monthly Subscription$0.491 Month
  • Semi-Annual Subscription$2.996 Months
  • Annual Subscription$5.991 Year
One-time1
  • Lifetime Purchase$9.99

Questions

Is Plus42 free?
Plus42 costs $9.99, with no in-app purchases.
Is RLM free?
RLM is free to download, with in-app purchases available.
Which has better reviews, Plus42 or RLM?
Plus42 is rated higher. Plus42 averages 4.9 out of 5 from 79 ratings, while RLM averages 3.1 from 7 ratings.
Do Plus42 or RLM have ads?
Neither Plus42 nor RLM shows ads.
Which is updated more often, Plus42 or RLM?
Plus42 ships an update weekly, and RLM every 5 weeks. Most recently, Plus42 was updated on September 22, 2026 and RLM on September 10, 2026.

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