Halcyon Calc vs SwiftRPN
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Halcyon Calc
A powerful calculator app for students, engineers, and scientists. It handles complex numbers, symbolic expressions, unit conversions, and matrix operations, with advanced plotting and programming capabilities.
- Complex number calculations
- Symbolic expression manipulation
- Unit conversion with custom units
- Matrix and vector operations
- Symbolic plotting
- Programming of custom operations
- Statistical data analysis
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For students, engineers, scientists or people who fondly remember classic calculators, Halcyon Calc 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 - Use over 120 built-in units to perform unit conversion or create your own units if the one you want is not already there - 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. Create hierarchies of symbols to allow you to organize your calculations. - Create sequences of calculator commands into programs, creating your own operations which you can then include in expressions. - 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.
SwiftRPN
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SwiftRPN is an RPN (Reverse Polish Notation) calculator that aims to be quick to open and easy to use. = RPN Stack Work quickly and efficiently using the RPN Stack by pushing and popping values. The stack will always show what series of inputs led to each output, so you won't lose context during complicated expressions. = Extended Types SwiftRPN can understand scalar types like integers and real numbers, as well as vectors and square matrices of sizes 2, 3, and 4. When operating purely in the scalar integer domain, SwiftRPN can promote up to BigInts to avoid floating point imprecision. = Operators SwiftRPN has 84 built-in operators with included documentation and examples. All the expected operators (basic arithmetic, exponents, logarithms) are present, as are: - Rounding functions (floor/ceil/trunc/round) - Unit conversions - Bitwise operations (and/or/not/xor/shift left/shift right) - Statistics (avg/min/max/sum/std dev/NPV) - Trigonometry (sin/cos/tan + arc/hyperbolic variants) - Vector operations (dot/cross/normalize/length/swizzle) - Matrix operations (identity/inverse/transpose + translation/scale/rotation matrix generators) = Unit Conversions SwiftRPN has 74 built-in units, and can convert between units within families, including: - Angle - Area - Colors (3 and 4 components) - Coordinate systems (2D and 3D) - Length - Mass - Storage (Base 10 [SI, 1000 bytes in a kb] and Base 2 [1024 bytes in a kb]) - Temperature - Time - Volume = Value Representation SwiftRPN recognizes values represented in binary, octal, decimal, and hexidecimal. You can: - Enter values in one representation, and convert them to another - See the result of bitwise operations in binary automatically - View vec3 and vec4 components (truncated) in hexidecimal when working with colors.
Screenshots
Verdict
The clearest difference is price: SwiftRPN at Free against Halcyon Calc's $4.99. Halcyon Calc's advantage is update cadence (every 4 months vs every 14 months) and ratings volume (18 vs 1). On rating, ads, in-app purchases 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
SwiftRPN is free to download; Halcyon Calc costs $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 4.9 for Halcyon Calc against 5.0 for SwiftRPN. That said, the two scores are not equally well evidenced: Halcyon Calc has 18 ratings behind it against 1, so its average is the more settled of the two.
Halcyon Calc ships an update every 4 months, SwiftRPN every 14 months. The most recent releases landed on October 23, 2026 and October 24, 2026 respectively.
| Parameter | Halcyon Calc | SwiftRPN |
|---|---|---|
| Price | $4.99 | Free — better |
| Rating | 4.9 (18 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 18 — better | 1 |
| Update frequency | Every 4 months — better | Every 14 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 16.6 — better | 17.6 |
| Further details — not scored | ||
| Size | 10 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | Halcyon Touch Software | Patrick Gelvin |
Customer experience
Halcyon Calc
SwiftRPN
In-app purchases
Halcyon Calc
No in-app purchases
SwiftRPN
No in-app purchases









