# RLM-15CX — Advance Scientific Calculator > Advanced programmable scientific calculator emulating HP-15C for iOS devices. (iPhone/iPad app by R.L.M. Software.) - Source: https://appshunter.io/ios/app/rlm-15cx/id1636646608 (this page in markdown: same URL + `.md`) - Developer: [R.L.M. Software](https://appshunter.io/developer/289639238) - Category: Productivity, Utilities - Price: Free with in-app purchases - Rating: 4.31/5 from 13 App Store ratings · 9 written reviews indexed - Age rating: 4+ - Requires: iOS 15.0 · 6 MB - Languages: English - Released: 2022-08-13 - Data updated: 2026-08-15 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/rlm-15cx/id1636646608/reviews.md ## What is RLM? The RLM-15CX application is a programable advanced scientific calculator. It is based in the Hewlett-Packard HP-15C calculator, but specially designed to bring up the most of your iOS devices and , at the same time, conserving the easy of use and the functionality 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 Cash Flows: Solve problems where different cash flows occur at regular time intervals. •Unequal Periods Cash Flows: Solve problems where different cash flows occur at different dates. •Depreciation: Calculates depreciation with SL, SOYD, DB or MACRS methods and conventions. values at sight. •Interest Rates: 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. •Matrix: view, create or edit matrices with real or complex elements. •Plane Triangle: Solves a two dimensional triangle (ASA,SAS,SSA and SSS). •Spherical Triangle: Solves a triangle in a sphere’s surface (AAA,AAS,ASA,SAS,SSA and SSS). •Universal Constants: All the NIST-CODATA fundamental physical constants. •Vectors 3D: Operations and functions with vectors in Cartesian, Spherical or Cylindrical coordinates. >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. •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 ## Key features - Programmable advanced scientific calculator - Finance and business calculation menus - Statistics and probability functions - Complex numbers and matrix operations - Unit and currency conversions - Equation solver and programming capabilities ## Pricing and in-app purchases Base price: Free. **Subscriptions** | Subscription | Price | Period | | --- | --- | --- | | Annual Subscription | $5.99 | per year | | Semi-Annual Subscription | $2.99 | per 6 months | | Monthly Subscription | $0.49 | per month | **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | One-Time Purchase | $9.99 | one-time | ## Recent user reviews (9 of 9) All indexed reviews: https://appshunter.io/ios/app/rlm-15cx/id1636646608/reviews.md ### 4/5 — HP15C_user *2026-02-19* The pressure conversion in this calculator uses seawater. For example, 20 psi is converted to 45.2412 feet of sea water. Using sea water is not common, and the calculator does not provide feet of standard water for a conversion unit. The conventional conversion is 20 psi is 46.1358 feet of standard water. ### 1/5 — Bait and switch! *2025-08-25* No price down in App Store, but upon install, immediately demand $9.99. NOPE ### 5/5 — Amazing & Impressive!! *2025-06-02* clearly, a work of love! So much attention to detail, not only to the functionality, but also to the visual looks.. the UI is super impressive! It really looks like a HP calculator! 🥰 kudos to your amazing and very impressive work! ### 5/5 — Amazing & Impressive!! *2025-05-29* clearly, a work of love! So much attention to detail, not only for the functionality, but also for the visual looks.. the UI is super impressive! It really looks like a HP calculator! 🥰 kudos to your amazing and very impressive work! ### 5/5 — Great app *2024-05-15* Obviously a work of love from someone who cares. I used an hp15c for most of my working life and this app is a faithful recreation of that experience. With this revision the intermittent lag is gone. Thanks to the developer for quickly responding. I give the app five stars now. **Developer response:** Do this intermitent lag still occurs ?, please contact us to support@rlmtools.com to have more information about. ### 4/5 — Great app *2024-05-05* Obviously a work of love from someone who cares. I used an hp15c for most of my working life and this app is a faithful recreation of that experience. I do find that there is an intermittent lag time between button presses and data entry. Otherwise, this is perfect. **Developer response:** Do this intermitent lag still occurs ?, please contact us to support@rlmtools.com to have more information about. ### 3/5 — Latest update disabled. *2024-03-08* Great app, but cannot restore purchase with today’s update. **Developer response:** We are very sorry for that, but be sure you are using the same Apple ID used in your first purchase. If it is ok, please refer to Apple's customer support. They completely control the installation, payments and restoring. ### 5/5 — “Clear” “REG” doesn’t clear the registers *2023-09-04* Great for money, except “Clear” “REG” doesn’t clear the registers. This is a bug that needs fixed ASAP. **Developer response:** This bug was fixed in the latest update. Please update to it (version 2.1.7). ### 5/5 — All better now *2022-10-19* With my settings fixed, this is now my go-to calculator on my phone. It is a bit pricey, but so was my 15C. **Developer response:** It seems that you have set to ON the “Button Shapes” option in the “Display & Text Size” of the “Accessibility” settings. So, open the device Settings, scroll down to the “Accessibility” item and touch it. Then, touch the “Display & Text Size” item and turn OFF the “Button Shapes” switch. ## Frequently asked questions about RLM ### What is RLM-15CX? RLM-15CX is a programmable advanced scientific calculator application for iOS devices. It is designed to replicate the functionality of the Hewlett-Packard HP-15C calculator while leveraging the capabilities of modern smartphones and tablets. ### What types of calculations can RLM-15CX perform? RLM-15CX offers extensive calculation capabilities across finance, business, statistics, scientific functions, unit conversions, and programming. It includes features like loan amortization, bond pricing, complex number operations, matrix manipulation, and probability distributions. ### Does RLM-15CX support programming? Yes, RLM-15CX features a dedicated program menu that allows users to create, edit, and load custom programs, similar to the original HP-15C calculator. ### What are the subscription options for RLM-15CX? RLM-15CX offers several subscription plans: a Monthly Subscription for $0.49, a Semi-Annual Subscription for $2.99, and an Annual Subscription for $5.99. ### What devices is RLM-15CX compatible with? RLM-15CX is compatible with iPhones, iPads, and iPods, running on iOS. It is rated for ages 4 and up. ### How often is RLM-15CX updated? The latest version of RLM-15CX is 2.1.7, and it was last updated on April 26, 2024. This indicates a relatively active development cycle. ### What is the user rating for RLM-15CX? RLM-15CX has a user rating of 4.3 stars based on 13 ratings, suggesting a generally positive user experience. ### Can RLM-15CX solve arbitrary algebraic equations? Yes, RLM-15CX includes a Solver Menu that allows users to enter and save arbitrary algebraic equations. It then creates a menu of all variables, enabling users to solve for any of them. ## Version history (last 5 releases) ### 2.1.7 — 2024-04-26 Now you can listen music while using the calculator. ### 2.1.6 — 2024-04-04 New editor for the Unit Conversion Database. Fix a problem with some devices involving the edition of a units conversions and categories in the database. ### 2.1.5 — 2024-03-07 Fix a bug regarding Accessibility Setting that affect the look of the interface. Now is always drawn well. ### 2.1.4 — 2024-02-18 Fix the issue of Currency Exchange menu where the "Get Rate" stop working since February 16th, 2024. ### 2.1.3 — 2024-01-29 Fix a bug regarding rectangular conversion in complex mode. ## Apps similar to RLM | App | Rating | Price | Category | | --- | --- | --- | --- | | [WP 31s](https://appshunter.io/ios/app/wp-31s/id973621300) | 4.9 (15) | Free | Productivity | | [RPN-70 SD](https://appshunter.io/ios/app/rpn-70-sd/id738422213) | 4.7 (11) | Free | Productivity | | [DB40X](https://appshunter.io/ios/app/db40x/id6624315901) | 4.7 (7) | Free | Productivity | | [WP 34s](https://appshunter.io/ios/app/wp-34s/id620255094) | 4.7 (28) | Free | Productivity | | [RPN-67 NP](https://appshunter.io/ios/app/rpn-67-np/id603100249) | 3.7 (3) | Free | Productivity | | [DB50X](https://appshunter.io/ios/app/db50x/id6625971367) | 5.0 (8) | $9.99 | Productivity | ## More apps by R.L.M. Software - [RLM-10BX](https://appshunter.io/ios/app/rlm-10bx/id1563019331) - [RLM-17BX](https://appshunter.io/ios/app/rlm-17bx/id1593889938) - [RLM-19BX](https://appshunter.io/ios/app/rlm-19bx/id1597086394) - [RLM-12CX](https://appshunter.io/ios/app/rlm-12cx/id1613759385) - [RLM-12PX](https://appshunter.io/ios/app/rlm-12px/id1613770734) - [RLM-11CX](https://appshunter.io/ios/app/rlm-11cx/id1630739014) All apps by R.L.M. Software: https://appshunter.io/developer/289639238 ## Related topics [hp 15c calculator](https://appshunter.io/ios/topics/hp-15c-calculator) · [hp 15c](https://appshunter.io/ios/topics/hp-15c) · [hp rpn calculator](https://appshunter.io/ios/topics/hp-rpn-calculator) --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-15.*