Comparison

WP 31s vs RLM

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

Head to head
About

WP 31s

This app emulates a classic RPN scientific calculator, offering a rich function set for daily use with a simplified interface. It's based on the more complex WP 34s but is designed for easier operation.

Highlights
  • RPN scientific calculator emulation
  • Rich function set
  • Simplified, less cluttered keyboard
  • Based on WP 34s
  • Available on iOS
Features
Read full description

WP 31s is a classic RPN scientific calculator based on the powerful but more complex WP 34s. Now available on iOS too (see the support site for other emulators and for the real stuff). It is not programmable but has a rich function set for daily use and is easier to use, thanks to a less cluttered keyboard. A manual can be downloaded at http://sourceforge.net/projects/wp34s/files/doc/Manual_wp_31s_1_2q.pdf/download

About

RLM

This advanced scientific calculator emulates the functionality of the HP-15C, offering comprehensive tools for finance, business, statistics, and scientific calculations. It supports programming, equation solving, and unit conversions, optimized for iOS devices.

Highlights
  • Programmable advanced scientific calculator
  • Finance and business calculation menus
  • Statistics and probability functions
  • Complex numbers and matrix operations
  • Unit and currency conversions
  • Equation solver and programming capabilities
Features
Read full description

The RLM-15CX application is a programable advanced scientific calculator. It is based in the Hewlett-Packard HP-15C calculator, but specially designed to bring up the most of your iOS devices and , at the same time, conserving the easy of use and the functionality 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 Cash Flows: Solve problems where different cash flows occur at regular time intervals. •Unequal Periods Cash Flows: Solve problems where different cash flows occur at different dates. •Depreciation: Calculates depreciation with SL, SOYD, DB or MACRS methods and conventions. values at sight. •Interest Rates: 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. •Matrix: view, create or edit matrices with real or complex elements. •Plane Triangle: Solves a two dimensional triangle (ASA,SAS,SSA and SSS). •Spherical Triangle: Solves a triangle in a sphere’s surface (AAA,AAS,ASA,SAS,SSA and SSS). •Universal Constants: All the NIST-CODATA fundamental physical constants. •Vectors 3D: Operations and functions with vectors in Cartesian, Spherical or Cylindrical coordinates. >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. •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

WP 31s1 screens
RLM4 screens

Verdict

The call

The clearest difference is rating: WP 31s at 4.9 against RLM's 4.1. WP 31s also leads on in-app purchases (none vs 4) and review sentiment (100% vs 80%). RLM's advantage is update cadence (monthly vs every 10 months). On price, ratings volume, 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

Both are free to download. RLM sells 4 in-app purchases, starting at $0.49 per month. WP 31s asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

WP 31s holds the better App Store score, 4.9 against 4.1. Both are backed by a comparable volume of ratings — 15 and 17 respectively. Written reviews point the same way: 100% of WP 31s's written reviews are positive against 80% of RLM's.

UpkeepUpdate frequency

WP 31s ships an update every 10 months, RLM monthly. The most recent releases landed on June 11, 2026 and September 10, 2026 respectively.

Scorecard6 real differences · 4 level
WP 31s versus RLM: the parameters behind the verdict, then further details
ParameterWP 31sRLM
PriceFreeFree
Rating4.9 (15 ratings) — better4.1 (17 ratings)
Positive reviews100.0% of reviews — better80.0% of reviews
Number of ratings1517 — better
Update frequencyEvery 10 monthsMonthly — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS12.0 — better15.0
Further details — not scored
Size16 MB6 MB
Age rating4+4+
DeveloperPascal MeheutR.L.M. Software

Customer experience

WP 31s

All ratings15 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews11 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

RLM

All ratings17 ratings
Positive70.6%
Neutral11.8%
Negative17.6%
Written reviews15 reviews
Positive80.0%
Neutral13.3%
Negative6.7%

In-app purchases

None

WP 31s

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
  • One-Time Purchase$9.99

Questions

Is WP 31s free?
WP 31s is free to download, with no in-app purchases.
Is RLM free?
RLM is free to download, with in-app purchases available.
Which has better reviews, WP 31s or RLM?
WP 31s is rated higher. WP 31s averages 4.9 out of 5 from 15 ratings, while RLM averages 4.1 from 17 ratings.
Do WP 31s or RLM have ads?
Neither WP 31s nor RLM shows ads.
Which is updated more often, WP 31s or RLM?
WP 31s ships an update every 10 months, and RLM monthly. Most recently, WP 31s was updated on June 11, 2026 and RLM on September 10, 2026.

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