Free42 vs SwiftRPN
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Free42
This application is a faithful re-implementation of the HP-42S scientific calculator and its associated printer. It offers full functionality without requiring original HP ROM images and is an open-source project.
- HP-42S calculator simulation
- HP-82240 printer simulation
- Open source project
- No HP ROM required
- Complete rewrite
Read full descriptionHide full description
Free42 is a re-implementation of the HP-42S calculator and the HP-82240 printer. It is a complete rewrite, not using any HP code, and it does not require an HP-42S ROM image. Free42 is an Open Source project. The executables and source code are released under the terms of the GNU General Public License, version 2. All third-party code used in Free42 is either in the public domain, or licensed under terms compatible with GPLv2, or used with the authors' permission.
SwiftRPN
This utility app provides a powerful Reverse Polish Notation (RPN) calculator with advanced features. It supports scalar types, vectors, and matrices, along with extensive built-in operators and unit conversions. Easily switch between number bases and visualize results.
- RPN stack for efficient calculations
- Support for scalar, vector, and matrix types
- 84 built-in operators with documentation
- 74 built-in units for conversion
- Multiple number base input and output (binary, octal, decimal, hex)
- BigInt support for integer calculations
Read full descriptionHide full description
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 update cadence: Free42 at every 9 days against SwiftRPN's every 14 months. Free42 also leads on ratings volume (287 vs 1) and iOS requirement (15.0 vs 17.6). SwiftRPN's advantage is rating (5.0 vs 4.8). On price, ads, in-app purchases and monetization model 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. Neither carries in-app purchases, so what you see is what you pay.
SwiftRPN holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: Free42 has 287 ratings behind it against 1, so its average is the more settled of the two.
Free42 ships an update every 9 days, SwiftRPN every 14 months. The most recent releases landed on October 29, 2026 and October 27, 2026 respectively.
| Parameter | Free42 | SwiftRPN |
|---|---|---|
| Price | Free | Free |
| Rating | 4.8 (287 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 94.4% of reviews | — |
| Number of ratings | 287 — better | 1 |
| Update frequency | Every 9 days — better | Every 14 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 15.0 — better | 17.6 |
| Further details — not scored | ||
| Size | 9 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | Thomas Okken | Patrick Gelvin |
Customer experience
Free42
SwiftRPN
Bugs and requests
Free42
Reported bugs
2 issues- Occasional issues with Solver function
- Store and Recall functions not working properly
Requested features
3 requests- Display all registers (X, Y, Z, T, Last X) simultaneously
- Ability to share/transfer programs between devices
- Improved use of screen real estate on larger displays
SwiftRPN
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Free42
No in-app purchases
SwiftRPN
No in-app purchases









