Comparison

RLM vs HP16C

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

Head to head
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.

About

HP16C

This app faithfully recreates the legendary HP 16C Computer Scientist calculator, offering advanced hex arithmetic, bit manipulation, and base conversion. It features RPN, keystroke programming, and modern enhancements like a two-line display and haptic feedback.

Highlights
  • Full RPN calculator
  • Integer arithmetic (HEX, DEC, OCT, BIN)
  • Configurable word size (1-64 bits)
  • Complete bit operations
  • Keystroke programming
  • Two-line display
  • Haptic feedback
Features
Read full description

A faithful recreation of the legendary HP 16C Computer Scientist calculator for iPhone, with a few modern upgrades. If you've ever needed to perform hex arithmetic, bit manipulation, or base conversion on your phone and been frustrated by the available options, this is for you. RPN-16C gives you the full power of the original HP 16C in your pocket. WHAT IT DOES - Full RPN (Reverse Polish Notation) calculator - Integer arithmetic in HEX, DEC, OCT, and BIN - Configurable word size from 1 to 64 bits - Unsigned, one's complement, and two's complement modes - Complete bit operations: shift, rotate, rotate through carry, AND, OR, XOR, NOT, mask, bit set/clear/test, count bits, left justify - Float mode with configurable precision (FLOAT 0-9) - Keystroke programming with labels, subroutines, loops, and conditionals - Storage registers with direct and indirect addressing - Programs can be imported from text (long-press the display to paste) ENHANCEMENTS OVER THE ORIGINAL - Two-line display: see both X and Y registers at once. No more guessing what's on the stack. - Wider LCD: displays all 32 bits in binary without scrolling. The original could only show 8 at a time. - Haptic feedback on every key press - State persistence: pick up right where you left off - SHOW function to peek at values in other bases FAIR WARNING This is a quirky calculator. It uses Reverse Polish Notation, has no equals key, and expects you to know what two's complement means. If you're looking for a simple calculator, this is not it. If you've ever wished you could do a bitwise rotate through carry on your phone, welcome home. DESIGNED FOR PROGRAMMERS The key layout matches the physical HP 16C exactly, including the f (gold) and g (blue) shift labels. If you know the original, you already know this one. The original HP 16C Owner's Handbook is freely available on the Internet Archive: https://archive.org/details/hp-16c_handbook

Screenshots

RLM4 screens
HP16C4 screens

Verdict

The call

The clearest difference is rating: HP16C at 4.3 against RLM's 3.1. HP16C also leads on in-app purchases (none vs 4) and update cadence (weekly vs every 5 weeks). RLM's advantage is iOS requirement (15.0 vs 17.0). 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. HP16C asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

HP16C holds the better App Store score, 4.3 against 3.1. Both are backed by a comparable volume of ratings — 7 and 4 respectively.

UpkeepUpdate frequency

RLM ships an update every 5 weeks, HP16C weekly. The most recent releases landed on October 30, 2026 and October 24, 2026 respectively.

Scorecard5 real differences · 5 level
RLM versus HP16C: the parameters behind the verdict, then further details
ParameterRLMHP16C
PriceFreeFree
Rating3.1 (7 ratings)4.3 (4 ratings) — better
Positive reviews40.0% of reviews—
Number of ratings7 — better4
Update frequencyEvery 5 weeksWeekly — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree — better
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.0 — better17.0
Further details — not scored
Size6 MB1 MB
Age rating4+4+
DeveloperR.L.M. SoftwareMichael Doornbos

Customer experience

RLM

All ratings7 ratings
Positive42.9%
Neutral14.3%
Negative42.9%
Written reviews5 reviews
Positive40.0%
Neutral0.0%
Negative60.0%

HP16C

All ratings3 ratings
Positive66.7%
Neutral33.3%
Negative0.0%

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
None

HP16C

No in-app purchases

Questions

Is RLM free?
RLM is free to download, with in-app purchases available.
Is HP16C free?
HP16C is free to download, with no in-app purchases.
Which has better reviews, RLM or HP16C?
HP16C is rated higher. RLM averages 3.1 out of 5 from 7 ratings, while HP16C averages 4.3 from 4 ratings.
Do RLM or HP16C have ads?
Neither RLM nor HP16C shows ads.
Which is updated more often, RLM or HP16C?
RLM ships an update every 5 weeks, and HP16C weekly. Most recently, RLM was updated on October 30, 2026 and HP16C on October 24, 2026.

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