WP 31s vs RLM
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
- RPN scientific calculator emulation
- Rich function set
- Simplified, less cluttered keyboard
- Based on WP 34s
- Available on iOS
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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
RLM
This app offers a comprehensive suite of financial, business, scientific, and statistical calculators. It includes specialized worksheets for loan amortization, bond pricing, currency exchange, probability distributions, and complex number operations. Users can also perform date and time calculations, solve arbitrary equations, and convert units.
- Finance worksheets (amortization, bonds, options)
- Business tools (bill split, break-even, currency)
- Statistical analysis (probability, regressions)
- Scientific functions (complex numbers, vectors)
- Unit and currency conversions
- Equation solver
- Date and time calculations
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The RLM-19BII is a general purpose calculator with a special focus in finance, business and science. It is designed to bring up the most of your iOS devices with an extensive set of worksheets and enhancements to cover most of the functions generally needed by financial, business, mathematical, engineering and scientific professionals. >Finance Worksheets: •Account Balance: Calculates the Balance of cash transactions and interest applied at arbitrary dates. •Amortization: Loan Amortization Schedule for a single or several loan payments. •Bond Price & Yield: Calculates the Price, Yield and Effective Duration of a Bond. •Black-Scholes Options: Calculates the CALL, PUT and “Greeks” values of a Black-Scholes European option. •Depreciation: Calculates depreciation with SL, SOYD, DB or MACRS methods and conventions. •Time Value of Money: Calculates compound Interest problems. >Business Worksheets: •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 manual or on-line rates. •Percents & Margins: Calculates %Change, %Total and Business margins. >Cash Flows Worksheets: •Equal Periods: Calculations with Cash Flows occurring at regular time intervals. •Unequal Periods: Calculations with Cash Flows occurring at arbitrary dates. >Statistics Worksheets: •Probability: Combinations, permutations and Normal, Exponential, t-Student and Weibull probability distributions. •One-Variable Statistics: Calculations for one variable data samples. •Two-Variable Statistics: Calculations for two variables data samples. •Curve Fitting: Regression models to fit a curve based on two variables data samples. >Scientific Worksheets: •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. >Conversion Worksheets: •Angles: Convert angle between DEG,RAD,GRAD,DMS and Slope %. •Currencies: world currencies conversions with manual input or on-line current rates. •Interest Rates: Nominal and effective interest conversion. •Polar-Rectangular: Coordinates conversion. •Units: Physical units conversions. >General Worksheets: •Date: Calculates days between dates with Actual, 360 or 365 days calendars. •Time: Calculates time intervals between different times. •Solver: Calculates arbitrary equations entered as text expression to solve any of the variables knowing the others. •Storage Registers: Store and perform operations directly over the calculators storage registers. •Memory Content: Clear, Back-Up or Restore part or all of the Calculator's memory. •General Settings: Customize many aspects of the calculator including formats & feedbacks. •Help Documents: Description and examples of all the calculator worksheets and features. >Editors Worksheets: To create or edit data •(Date,Trx) List: Transactions and the dates they occurs for the "Account Balance Worksheet". •(Date.CF) List: Cash flows and the dates they occurs for the "Unequal Periods Cash Flows Worksheet". •(X,N) List: Cash flows and repetitions for the "Equal Periods Cash Flows Worksheet". •(X,Y) List: X and Y data samples for the Statistics worksheets. •Solver Equation: Algebraic expression for use in the "Solver" worksheet. •Units Database: Customize the "Units" worksheet. 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
Verdict
The clearest difference is in-app purchases: WP 31s at none against RLM's 4. WP 31s also leads on review sentiment (100% vs 67%) and iOS requirement (12.0 vs 15.0). RLM's advantage is update cadence (every 3 weeks vs every 10 months). On price, rating, ratings volume and ads 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
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.
On the App Store both sit at effectively the same score — 4.9 for WP 31s against 4.9 for RLM. Both are backed by a comparable volume of ratings — 15 and 7 respectively. Written reviews are what separate them: 100% of WP 31s's written reviews are positive against 67% of RLM's.
WP 31s ships an update every 10 months, RLM every 3 weeks. The most recent releases landed on June 11, 2026 and September 10, 2026 respectively.
| Parameter | WP 31s | RLM |
|---|---|---|
| Price | Free | Free |
| Rating | 4.9 (15 ratings) | 4.9 (7 ratings) |
| Positive reviews | 100.0% of reviews — better | 66.7% of reviews |
| Number of ratings | 15 — better | 7 |
| Update frequency | Every 10 months | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.0 — better | 15.0 |
| Further details — not scored | ||
| Size | 16 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | Pascal Meheut | R.L.M. Software |
Customer experience
WP 31s
RLM
In-app purchases
WP 31s
No in-app purchases
RLM
- Monthly Subscription$0.491 Month
- Semi-Annual Subscription$2.996 Months
- Annual Subscription$5.991 Year
- Lifetime Purchase$9.99





