RPN vs RLM
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RPN
This app is a faithful simulation of a rare 1974 financial calculator, offering all its original functions with enhanced features like more memory registers and a visual stack display. It's designed for users who appreciate vintage technology and need precise financial calculations.
- Photo-realistic vintage calculator design
- Full HP-70 function simulation
- Animated keys with sound
- Enhanced stack and memory register view
- Cut/copy/paste display value
- Input parameter visual indicators
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RPN-70 SD is a complete simulation of the financial hand-held calculator HP-70 from 1974. It handles loan amortization, saving plans, depreciation, and much more with ease. What users said: "Looks good, all functions you need. Love it!" "This is a beautiful emulation of a very rare HP financial calculator from 1974. Works just like the original but better! Faster, more accurate, with 10 more storage registers, and a popup window lets you see the contents of each stack, financial and storage register. Provides TVM4 functionality for compound interest as well as accumulated simple interest. A true work of art!" Features: • Photo-realistic look based on an existing device • Animated keys with click sound (adjustable volume) • All functions and operations of the HP-70 fully implemented • Correct wrong number entries by swiping across the display • Cut/copy/paste of display value • Double-tap display to view the stack and memory registers • Visual indicators keep track of input parameters entered • 10 non-volatile memory registers (not available in original HP-70) The HP-70 was discontinued after just one year. It is one of the rarest calculators, hard to find in any condition. NOTE: RPN-70 SD is a faithful simulation of a vintage HP-70 calculator, as has been verified against a real device using the examples in the Applications Cookbook section of the HP-70 manual. In certain cases, what may appear like a bug of the app is actually an idiosyncrasy of the HP-70. IMPORTANT: The HP-70 requires exactly three input parameters from the top-row keys, at least one of them being either "n" or "i". In other words, you can't use PMT, PV, and FV as input parameters simultaneously. A version for the iPhone named "RPN-70 HD" is also available. Short manual and sample calculations on the website: www.cuveesoft.ch
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-19BX is a calculator for 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. •Interest Rates: Nominal and effective interest conversion. •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. •Inventory Turn Over. •Percents & Margins: Calculates %Change, %Total and Business margins. •Return on Investment. >Cash Flows Worksheets: •Equal Periods: Cash Flows occurring at regular time intervals. •Unequal Periods: Cash Flows occurring at arbitrary dates. >Statistics Worksheets: •Probability: 16 probability distributions. •One or Two variables Statistics. •Curve Fitting: 6 Regression models to fit a curve. >Scientific Worksheets: •Angles & Polar-Rectangular conversions. •Complex Numbers: Operations and functions with complex numbers. •Combinations & Permutations. •Logarithms, Trigonometric, Hyperbolic and Number Alteration functions. •Quadratic Equation solver •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. •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. •General Settings to set classic and new keyboard skins, RPN and algebraic logic, sounds, display format, etc. >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 26.0 or above. 30-day free trial, then a single one-time Lifetime Purchase. No subscription. 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: RPN at none against RLM's 4. RPN also leads on review sentiment (100% vs 67%) and iOS requirement (12.0 vs 26.0). RLM's advantage is update cadence (every 4 weeks vs every 7 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. RPN asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 4.7 for RPN against 4.9 for RLM. Both are backed by a comparable volume of ratings — 11 and 7 respectively. Written reviews are what separate them: 100% of RPN's written reviews are positive against 67% of RLM's.
RPN ships an update every 7 months, RLM every 4 weeks. The most recent releases landed on November 1, 2026 and November 3, 2026 respectively.
| Parameter | RPN | RLM |
|---|---|---|
| Price | Free | Free |
| Rating | 4.7 (11 ratings) | 4.9 (7 ratings) — better |
| Positive reviews | 100.0% of reviews — better | 66.7% of reviews |
| Number of ratings | 11 — better | 7 |
| Update frequency | Every 7 months | Every 4 weeks — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Devices | iPhone, iPod | iPhone, iPad |
| Requires iOS | 12.0 — better | 26.0 |
| Further details — not scored | ||
| Size | 17 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | CuVee Software | R.L.M. Software |
Customer experience
RPN
RLM
In-app purchases
RPN
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






