PCalc vs Free42
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PCalc
A powerful calculator designed for professionals and students, offering advanced features like RPN mode, multi-line display, and extensive unit conversions. It supports various number systems and includes an Apple Watch app for on-the-go calculations.
- Optional RPN mode
- Multi-line display
- Extensive unit conversions
- Paper tape
- Multiple undo/redo
- Hexadecimal, octal, binary support
- Apple Watch app
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PCalc is the powerful choice for scientists, engineers, students, programmers, or indeed anybody looking for a feature rich calculator. It includes an optional RPN mode and multi-line display, a choice of button layouts, an extensive set of unit conversions and constants, a paper tape, multiple undo and redo, engineering and scientific notation, as well as support for hexadecimal, octal, and binary calculations. Includes an Apple Watch app, so you can calculate on your wrist!
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
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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.
Screenshots
Verdict
The clearest difference is price: Free42 at Free against PCalc's $9.99. Free42 also leads on in-app purchases (none vs 4) and update cadence (every 9 days vs every 6 weeks). PCalc's advantage is chart position (#68 vs unranked) and device support (5 vs 3). On rating, ratings volume, ads and iOS requirement 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
Free42 is free to download; PCalc costs $9.99 up front. PCalc sells 4 one-off in-app purchases. Free42 asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 4.7 for PCalc against 4.8 for Free42. Both are backed by a comparable volume of ratings — 770 and 284 respectively. Written reviews are what separate them: 84% of PCalc's written reviews are positive against 94% of Free42's.
PCalc ships an update every 6 weeks, Free42 every 9 days. Both last shipped on October 18, 2026.
| Parameter | PCalc | Free42 |
|---|---|---|
| Price | $9.99 | Free — better |
| Rating | 4.7 (770 ratings) | 4.8 (284 ratings) — better |
| Positive reviews | 83.6% of reviews | 94.4% of reviews — better |
| Number of ratings | 770 — better | 284 |
| Update frequency | Every 6 weeks | Every 9 days — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Best chart rank | #68 — better | — |
| Devices | iPhone, iPad, iPod, Apple Watch, Vision Pro — better | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 15.0 |
| Further details — not scored | ||
| Size | 81 MB | 9 MB |
| Age rating | 4+ | 4+ |
| Developer | TLA Systems Ltd. | Thomas Okken |
Customer experience
PCalc
Free42
Bugs and requests
PCalc
Not enough reviews yet to summarise bugs or 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
In-app purchases
PCalc
- Small Tip$0.99
- Medium Tip$1.99
- Large Tip$4.99
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- Enormous Tip$9.99
Free42
No in-app purchases
