Halcyon Calc Lite vs RPNPro
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Halcyon Calc Lite
This app is a powerful calculator for students and professionals, offering advanced features like symbolic expression manipulation, graphing, and statistical analysis. It supports real, complex, and integer numbers, matrices, and vectors, making it versatile for various mathematical tasks.
- Symbolic expression manipulation
- Graphing of expressions
- Matrix and vector calculations
- Statistical analysis
- Multiple number formats (decimal, hex, octal, binary)
- Over 225 built-in operations
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For students, engineers, scientists or people who fondly remember classic calculators, Halcyon Calc Lite is a great application for manipulating numbers and even symbolic expressions. Features: - Use this calculator on an iPhone, iPod Touch or an iPad - Use your finger to quickly scroll through the stack to review intermediate results - Copy and paste support - Over 225 built-in operations, including trig, logarithms, real functions, complex operations and more - Allows you to work with real, complex and integer numbers. - Real and complex numbers can be displayed in standard, fixed, scientific and engineering format - Integer numbers can be displayed in decimal, hexadecimal, octal and binary bases - Work with real and complex matrices and vectors - Enter symbolic expressions and solve them for different values. Even better, solve quadratic formulas, collect and expand factors and terms, find minima, maxima and roots of any expression. - Plot symbolic expressions in X/Y coordinates. Pan the coordinate space by dragging the plot in any direction. Zoom in and out using a pinch gesture. - Determine symbolic derivative, taylor series or numeric integral of an expression. - Store numbers, lists, strings and expressions in symbols. - Store statistical data and calculate totals, averages, standard deviations, linear regressions, etc over that data. - Calculate the probabilities associated with standard distributions like the normal, F and T distributions.
RPNPro
This calculator utilizes Reverse Polish Notation (RPN) for input, mirroring the functionality of classic HP calculators. It features a four-level stack with X, Y, Z, and T registers, displaying the X register in decimal, hexadecimal, and binary.
- Reverse Polish Notation (RPN) input
- Four-level stack (X, Y, Z, T registers)
- Decimal, hexadecimal, and binary display
- Modeled after HP calculators
- Designed for software engineers
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RPNPro is a calculator for software engineers. RPNPro uses RPN (Reverse Polish Notation) as an input scheme. It is based on the same four level stack model as provided by the original HP (Hewlett-Packard) calculators, featuring X, Y, Z and T registers. The contents of the X register are always shown in decimal, hexadecimal and binary notation.
Screenshots
Verdict
The clearest difference is in-app purchases: RPNPro at none against Halcyon Calc Lite's 3. RPNPro also leads on ads (none vs shown) and rating (5.0 vs 4.7). Halcyon Calc Lite's advantage is update cadence (every 3 months vs every 37 months) and review sentiment (67% vs 50%). On price 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
Both are free to download. Halcyon Calc Lite sells 3 one-off in-app purchases. RPNPro asks for nothing beyond the download.
RPNPro holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Halcyon Calc Lite has 15 ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 67% of Halcyon Calc Lite's written reviews are positive against 50% of RPNPro's, so the app with the better star average is not the one people write more warmly about.
Halcyon Calc Lite ships an update every 3 months, RPNPro every 37 months. The most recent releases landed on October 15, 2026 and September 28, 2026 respectively.
| Parameter | Halcyon Calc Lite | RPNPro |
|---|---|---|
| Price | Free | Free |
| Rating | 4.7 (15 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 66.7% of reviews — better | 50.0% of reviews |
| Number of ratings | 15 — better | 1 |
| Update frequency | Every 3 months — better | Every 37 months |
| Ads | Yes | No — better |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 16.6 | 9.1 — better |
| Further details — not scored | ||
| Size | 13 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Halcyon Touch Software | Felix Meier |
Customer experience
Halcyon Calc Lite
RPNPro
In-app purchases
Halcyon Calc Lite
- Directory And Unit Conversion Support$0.99
- Programming Support$1.99
- Larger Display Upgrade$1.99
RPNPro
No in-app purchases









