RLM vs PiSquared
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-19BX is a calculator for 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. •Interest Rates: Nominal and effective interest conversion. •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. •Inventory Turn Over. •Percents & Margins: Calculates %Change, %Total and Business margins. •Return on Investment. >Cash Flows Worksheets: •Equal Periods: Cash Flows occurring at regular time intervals. •Unequal Periods: Cash Flows occurring at arbitrary dates. >Statistics Worksheets: •Probability: 16 probability distributions. •One or Two variables Statistics. •Curve Fitting: 6 Regression models to fit a curve. >Scientific Worksheets: •Angles & Polar-Rectangular conversions. •Complex Numbers: Operations and functions with complex numbers. •Combinations & Permutations. •Logarithms, Trigonometric, Hyperbolic and Number Alteration functions. •Quadratic Equation solver •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. •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. •General Settings to set classic and new keyboard skins, RPN and algebraic logic, sounds, display format, etc. >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 26.0 or above. 30-day free trial, then a single one-time Lifetime Purchase. No subscription. 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.
PiSquared
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PiSquared is an RPN-only calculator for the Apple Watch. It supports a wide variety of mathematical and scientific functions as well as binary operations for programmers. Integer, floating point (real) and complex numbers are equally supported. These functions are available: - calculation of the number of combinations or permutations for integer numbers - factorials for integer numbers or Gamma function for positive non-integer numbers - trigonometric, logarithmic, exponential and hyperbolic functions for floating point and complex numbers - date and time conversions - logical operations for binary, octal or hexadecimal numbers - cartesian to polar coordinate conversions and vice versa (floating point numbers) - degrees to radians and vice versa conversions (floating point numbers) - absolute, integer and fractional value of a number (floating point and partially complex numbers) - rounding of a real number (standard rounding and rounding up or down) - random number generator and some more. The calculator has a stack depth of ten and features ten additional storage registers. All storage registers and the stack can be inspected. The stack itself can be manipulated by moving it up or down or by swapping its two topmost elements.
Screenshots
Verdict
The clearest difference is price: RLM at Free against PiSquared's $1.99. RLM also leads on update cadence (every 4 weeks vs every 23 months). PiSquared's advantage is in-app purchases (none vs 4) and iOS requirement (13.0 vs 26.0). On 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
RLM is free to download; PiSquared costs $1.99 up front. RLM sells 4 in-app purchases, starting at $0.49 per month. PiSquared asks for nothing beyond the download.
RLM ships an update every 4 weeks, PiSquared every 23 months. The most recent releases landed on October 24, 2026 and October 15, 2026 respectively.
| Parameter | RLM | PiSquared |
|---|---|---|
| Price | Free — better | $1.99 |
| Rating | 4.9 (7 ratings) — better | — |
| Positive reviews | 66.7% of reviews | — |
| Number of ratings | 7 — better | — |
| Update frequency | Every 4 weeks — better | Every 23 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad | iPhone, iPod, Apple Watch — better |
| Requires iOS | 26.0 | 13.0 — better |
| Further details — not scored | ||
| Size | 7 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | R.L.M. Software | Hartwig Wiesmann |
In-app purchases
RLM
- Monthly Subscription$0.491 Month
- Semi-Annual Subscription$2.996 Months
- Annual Subscription$5.991 Year
- Lifetime Purchase$9.99
PiSquared
No in-app purchases









