Comparison

Complex RPN Calculator vs RLM

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

Head to head
About

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.

Highlights
  • Complex number support
  • Four-level stack
  • Polar and rectangular formats
  • State persistence
  • 10 memory locations
  • Scientific calculations
Features
Read full description

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.

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

Complex RPN Calculator4 screens
RLM4 screens

Verdict

The call

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

CostPrice · In-app purchases · Ads · Monetization

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.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard6 real differences · 4 level
Complex RPN Calculator versus RLM: the parameters behind the verdict, then further details
ParameterComplex RPN CalculatorRLM
PriceFreeFree
Rating3.8 (22 ratings) — better3.1 (7 ratings)
Positive reviews51.7% of reviews66.7% of reviews — better
Number of ratings22 — better7
Update frequencyEvery 5 monthsEvery 5 weeks — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS16.415.0 — better
Further details — not scored
Size1 MB6 MB
Age rating4+4+
DeveloperJohn CoddingtonR.L.M. Software

Customer experience

Complex RPN Calculator

All ratings22 ratings
Positive72.7%
Neutral0.0%
Negative27.3%
Written reviews87 reviews
Positive51.7%
Neutral8.0%
Negative40.2%

RLM

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

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)
Show 1 more
  • 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)
Show 19 more
  • 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

None

Complex RPN Calculator

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 Complex RPN Calculator free?
Complex RPN Calculator 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, Complex RPN Calculator or RLM?
Complex RPN Calculator is rated higher. Complex RPN Calculator averages 3.8 out of 5 from 22 ratings, while RLM averages 3.1 from 7 ratings.
Do Complex RPN Calculator or RLM have ads?
Neither Complex RPN Calculator nor RLM shows ads.
Which is updated more often, Complex RPN Calculator or RLM?
Complex RPN Calculator ships an update every 5 months, and RLM every 5 weeks. Most recently, Complex RPN Calculator was updated on August 23, 2026 and RLM on September 10, 2026.

Other comparisons