Comparison

RLM vs HP

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

HP

Emulates classic Hewlett Packard RPN scientific calculators from the 1970s. Experience the original HP-35, HP-45, and HP-21 models on your iPhone.

Highlights
  • RPN calculator emulation
  • HP-35 model
  • HP-45 model
  • HP-21 model
  • Classic scientific calculator interface
Features
Read full description

The classic Hewlett Packard RPN (Reverse Polish Notation) calculators. - HP-35, HP-45. First pocket scientific calculators (1972).  - HP-21. 2nd gen of the HP-35 (1975)

Screenshots

RLM4 screens
HP4 screens

Verdict

The call

The clearest difference is rating: HP at 5.0 against RLM's 3.1. HP also leads on in-app purchases (none vs 4) and review sentiment (100% vs 67%). RLM's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 17.2). On price, 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. RLM sells 4 in-app purchases, starting at $0.49 per month. HP asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

HP holds the better App Store score, 5.0 against 3.1. Both are backed by a comparable volume of ratings — 7 and 5 respectively. Written reviews point the same way: 67% of RLM's written reviews are positive against 100% of HP's.

UpkeepUpdate frequency

RLM ships an update every 5 weeks, HP every 11 days. The most recent releases landed on September 10, 2026 and September 21, 2026 respectively.

Scorecard7 real differences · 3 level
RLM versus HP: the parameters behind the verdict, then further details
ParameterRLMHP
PriceFreeFree
Rating3.1 (7 ratings)5.0 (5 ratings) — better
Positive reviews66.7% of reviews100.0% of reviews — better
Number of ratings7 — better5
Update frequencyEvery 5 weeksEvery 11 days — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree — better
DevicesiPhone, iPad, iPod — betteriPhone
Requires iOS15.0 — better17.2
Further details — not scored
Size6 MB2 MB
Age rating4+4+
DeveloperR.L.M. SoftwareEnrique Haro

Customer experience

RLM

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

HP

All ratings5 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews3 reviews
Positive100.0%
Neutral0.0%
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

HP

No in-app purchases

Questions

Is RLM free?
RLM is free to download, with in-app purchases available.
Is HP free?
HP is free to download, with no in-app purchases.
Which has better reviews, RLM or HP?
HP is rated higher. RLM averages 3.1 out of 5 from 7 ratings, while HP averages 5.0 from 5 ratings.
Do RLM or HP have ads?
Neither RLM nor HP shows ads.
Which is updated more often, RLM or HP?
RLM ships an update every 5 weeks, and HP every 11 days. Most recently, RLM was updated on September 10, 2026 and HP on September 21, 2026.

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