Complex RPN Calculator vs RLM
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Complex RPN Calculator
This scientific calculator utilizes a four-level stack and natively handles complex numbers. It allows users to input and view numbers in both polar and rectangular formats, remembering its state and offering 10 memory locations.
- Complex number support
- Four-level stack
- Polar and rectangular formats
- State persistence
- 10 memory locations
- Scientific calculations
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Complex RPN Calculator is a scientific RPN calculator with a four stack whose native number is complex. You can view and enter numbers in both polar and rectangular formats. Complex RPN remembers its state between usages and has 10 memory locations.
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.
- 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
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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
Verdict
The clearest difference is rating: Complex RPN Calculator at 3.8 against RLM's 3.1. Complex RPN Calculator also leads on in-app purchases (none vs 4) and ratings volume (22 vs 7). RLM's advantage is update cadence (every 5 weeks vs every 5 months) and review sentiment (67% vs 52%). On price, ads, device support and iOS requirement 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. Complex RPN Calculator asks for nothing beyond the download.
Complex RPN Calculator holds the better App Store score, 3.8 against 3.1. Both are backed by a comparable volume of ratings — 22 and 7 respectively. Written reviews complicate that: 52% of Complex RPN Calculator's written reviews are positive against 67% of RLM's, so the app with the better star average is not the one people write more warmly about.
Complex RPN Calculator ships an update every 5 months, RLM every 5 weeks. The most recent releases landed on August 23, 2026 and September 10, 2026 respectively.
| Parameter | Complex RPN Calculator | RLM |
|---|---|---|
| Price | Free | Free |
| Rating | 3.8 (22 ratings) — better | 3.1 (7 ratings) |
| Positive reviews | 51.7% of reviews | 66.7% of reviews — better |
| Number of ratings | 22 — better | 7 |
| Update frequency | Every 5 months | Every 5 weeks — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 16.4 | 15.0 — better |
| Further details — not scored | ||
| Size | 1 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | John Coddington | R.L.M. Software |
Customer experience
Complex RPN Calculator
RLM
Bugs and requests
Complex RPN Calculator
Reported bugs
6 issues- Mutes other apps when used
- Slow keyboard response after update
- X^3 calculation incorrect for large imaginary numbers
- App crashes on opening/button press (historical iOS 9 issues)
- App starts upside down in landscape on iPad (historical iOS 8 issue)
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- Unreadable fonts on iPad (historical version 1.2 issue)
Requested features
24 requests- Turn off key click sound
- Customize number display
- See the stack
- Fix slow entry response
- Fix imaginary number calculation (X^3)
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- Improve SwiftUI design (less whitespace)
- Show all stack levels
- Add angle function
- Add magnitude function
- Add 'Clear X' button
- Make RAD/DEG toggle button
- Single button for Sci/Eng/Fix/Raw modes
- Add '//' (parallel) function
- Add 'Module' button
- Change 'i' to 'j' for imaginary part
- Show stack levels
- Add log2 function
- Add logGamma function
- Smaller buttons
- Add complex conjugate button
- Add real part button
- Add imaginary part button
- Add modulo function
- Make app start faster
RLM
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Complex RPN Calculator
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









