RLM vs DB40X
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RLM
This app offers a comprehensive suite of financial, business, scientific, and statistical calculators. It includes specialized worksheets for loan amortization, bond pricing, currency exchange, probability distributions, and complex number operations. Users can also perform date and time calculations, solve arbitrary equations, and convert units.
- Finance worksheets (amortization, bonds, options)
- Business tools (bill split, break-even, currency)
- Statistical analysis (probability, regressions)
- Scientific functions (complex numbers, vectors)
- Unit and currency conversions
- Equation solver
- Date and time calculations
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The RLM-19BII is a general purpose calculator with a special focus in finance, business and science. It is designed to bring up the most of your iOS devices with an extensive set of worksheets and enhancements to cover most of the functions generally needed by financial, business, mathematical, engineering and scientific professionals. >Finance Worksheets: •Account Balance: Calculates the Balance of cash transactions and interest applied at arbitrary dates. •Amortization: Loan Amortization Schedule for a single or several loan payments. •Bond Price & Yield: Calculates the Price, Yield and Effective Duration of a Bond. •Black-Scholes Options: Calculates the CALL, PUT and “Greeks” values of a Black-Scholes European option. •Depreciation: Calculates depreciation with SL, SOYD, DB or MACRS methods and conventions. •Time Value of Money: Calculates compound Interest problems. >Business Worksheets: •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 manual or on-line rates. •Percents & Margins: Calculates %Change, %Total and Business margins. >Cash Flows Worksheets: •Equal Periods: Calculations with Cash Flows occurring at regular time intervals. •Unequal Periods: Calculations with Cash Flows occurring at arbitrary dates. >Statistics Worksheets: •Probability: Combinations, permutations and Normal, Exponential, t-Student and Weibull probability distributions. •One-Variable Statistics: Calculations for one variable data samples. •Two-Variable Statistics: Calculations for two variables data samples. •Curve Fitting: Regression models to fit a curve based on two variables data samples. >Scientific Worksheets: •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. >Conversion Worksheets: •Angles: Convert angle between DEG,RAD,GRAD,DMS and Slope %. •Currencies: world currencies conversions with manual input or on-line current rates. •Interest Rates: Nominal and effective interest conversion. •Polar-Rectangular: Coordinates conversion. •Units: Physical units conversions. >General Worksheets: •Date: Calculates days between dates with Actual, 360 or 365 days calendars. •Time: Calculates time intervals between different times. •Solver: Calculates arbitrary equations entered as text expression to solve any of the variables knowing the others. •Storage Registers: Store and perform operations directly over the calculators storage registers. •Memory Content: Clear, Back-Up or Restore part or all of the Calculator's memory. •General Settings: Customize many aspects of the calculator including formats & feedbacks. •Help Documents: Description and examples of all the calculator worksheets and features. >Editors Worksheets: To create or edit data •(Date,Trx) List: Transactions and the dates they occurs for the "Account Balance Worksheet". •(Date.CF) List: Cash flows and the dates they occurs for the "Unequal Periods Cash Flows Worksheet". •(X,N) List: Cash flows and repetitions for the "Equal Periods Cash Flows Worksheet". •(X,Y) List: X and Y data samples for the Statistics worksheets. •Solver Equation: Algebraic expression for use in the "Solver" worksheet. •Units Database: Customize the "Units" worksheet. 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.
DB40X
A high-precision scientific calculator inspired by the HP48 series, offering arbitrary precision computations, complex numbers, vectors, matrices, and graphing. It supports RPN and algebraic operations, with over 1000 built-in functions and a hyperlinked help system.
- Arbitrary precision computations
- RPN and algebraic operations
- Complex numbers, vectors, and matrices
- Graphing and plotting
- Engineering units and conversions
- Hyperlinked help system
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DB40X is a high-precision scientific calculator compatible with DB48X and inspired by the legendary HP48 series from Hewlett-Packard. It is not an emulator, but a redesign from scratch, which is faster, and delivers never seen before capabilities like computations in arbitrary precision. Like the original HP48, DB40X supports an unlimited stack, RPN and algebraic operations, complex numbers, based numbers, vectors, matrices, text, symbolic computations, numerical solving and integration, graphing and plotting, statistics, engineering units, and well over 1000 built-in functions. DB40X adds several HP50G capabilities, including a library of equations and constants covering mathematics, physics or chemistry. Using modern technologies, DB40X goes well beyond the original HP48 in many ways: - It is significantly faster, uses less memory, and features a higher-resolution 240x400 pixels graphical display. - Integer and decimal values can have an arbitrarily large number of digits, so you can compute log(pi) with 200 digits in a few keystrokes. - The six function keys feature up to three function per key, giving quick access to up to 18 related functions at a time. - Complex numbers can mix and match polar and rectangular form. - Symbolic operations extend to complex numbers, vectors and matrices. - Based numbers can be in any base from 2 to 36, and support any number of bits, making it easy to emulate a 23-bit or 512-bit processor. - Text is represented using Unicode instead of the proprietary HP encoding, facilitating data exchange with the rest of the world. - Multiple graphs can be distinguished using bitmap patterns. - Engineering units include all the modern evolutions of the SI system, and can be configured by the user, e.g. to integrate currency units with the exchange rate du jour. Converting between USD/hour and EUR/day has never been so easy! - A built-in hyperlinked help system documents functions simply by holding the corresponding key, and combine a quick start guide, a user manual and a reference manual. DB40X will run many user RPL programs as is. However, since it is not an emulator, it will not run any HP binary object, and notably will not run HP48 games or anything involving system RPL. Version 0.7.14 is an early-access release. Please consult https://github.com/c3d/db48x/blob/stable/doc/5-Unimplemented.md for a list of HP48 commands that are not yet implemented. DB40X is part of a family of compatible RPL calculators that include DB48X and DB50X. DB40X lacks the ability to write programs or data to disk, and RPL programs are limited to 40K.
Screenshots
Verdict
The clearest difference is in-app purchases: DB40X at none against RLM's 4. On price, rating, review sentiment and ratings volume 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. DB40X asks for nothing beyond the download.
RLM holds the better App Store score, 4.9 against 4.7. Both are backed by a comparable volume of ratings — 7 and 7 respectively. Written reviews split almost evenly too, at 67% and 67% positive.
Both ship on a similar rhythm, roughly every 3 weeks. The most recent releases landed on September 10, 2026 and June 4, 2026 respectively.
| Parameter | RLM | DB40X |
|---|---|---|
| Price | Free | Free |
| Rating | 4.9 (7 ratings) — better | 4.7 (7 ratings) |
| Positive reviews | 66.7% of reviews | 66.7% of reviews |
| Number of ratings | 7 | 7 |
| Update frequency | Every 3 weeks | Every 3 weeks |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 14.0 — better |
| Further details — not scored | ||
| Size | 6 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | R.L.M. Software | Christophe de Dinechin |
Customer experience
RLM
DB40X
In-app purchases
RLM
- Monthly Subscription$0.491 Month
- Semi-Annual Subscription$2.996 Months
- Annual Subscription$5.991 Year
- Lifetime Purchase$9.99
DB40X
No in-app purchases









