PCalc Lite vs Free42
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PCalc Lite
This free scientific calculator offers essential features like RPN mode, unit conversions, and multiple undo/redo. It provides a taste of a more powerful version, with optional in-app purchases for expanded functionality.
- Optional RPN mode
- Multiple undo and redo
- Unit conversions and constants
- Two stylish themes
- 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.PCalc Lite is a fully functional and free taste of our very popular scientific calculator. It includes an optional RPN mode, multiple undo and redo, unit conversions and constants, as well as two stylish themes and our highly praised design. A great choice for your new iPad! If you like what you see, the full version has many more settings and themes, a paper tape, engineering and scientific notation, and full support for hexadecimal, octal, and binary calculations. You can also now purchase extra features directly from inside PCalc Lite. Buy them individually, or buy everything. Includes an Apple Watch app, so you can calculate on your wrist!
Free42
This app is a faithful, open-source simulation of the HP-42S scientific calculator and its associated printer. It offers a complete rewrite without requiring original ROM images, allowing users to run existing programs on their devices.
- HP-42S calculator simulation
- HP-82240 printer simulation
- Open Source project
- Runs original HP-42S programs
- No ROM image required
- Customizable skins
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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 in-app purchases: Free42 at none against PCalc Lite's 10. Free42 also leads on update cadence (weekly vs every 2 months) and rating (4.8 vs 4.4). On price, ratings volume, 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
Both are free to download. PCalc Lite sells 10 one-off in-app purchases. Free42 asks for nothing beyond the download.
Free42 holds the better App Store score, 4.8 against 4.4. Both are backed by a comparable volume of ratings — 214 and 288 respectively. Written reviews point the same way: 82% of PCalc Lite's written reviews are positive against 94% of Free42's.
PCalc Lite ships an update every 2 months, Free42 weekly. The most recent releases landed on October 31, 2026 and November 13, 2026 respectively.
| Parameter | PCalc Lite | Free42 |
|---|---|---|
| Price | Free | Free |
| Rating | 4.4 (214 ratings) | 4.8 (288 ratings) — better |
| Positive reviews | 82.5% of reviews | 94.4% of reviews — better |
| Number of ratings | 214 | 288 — better |
| Update frequency | Every 2 months | Weekly — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad, iPod, Apple Watch — better | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 15.0 |
| Further details — not scored | ||
| Size | 79 MB | 9 MB |
| Age rating | 4+ | 4+ |
| Developer | TLA Systems Ltd. | Thomas Okken |
Customer experience
PCalc Lite
Free42
User reviews
PCalc Lite
From 214 App Store ratingsWhat we love
- 🚀 Fast and responsive
- 👍 Clean and intuitive interface
- 💡 Customizable themes and settings
- 🚀 Efficient performance
- 👍 Useful conversion tools
Room to improve
- 🐛 Occasional lags and crashes
- 🔒 Lack of dark mode support
- 🔒 Inconsistent icon appearance after upgrades
- 🔒 Limitations in RPN mode on Apple Watch
- 🔒 Lack of financial calculator functions
Free42
From 288 App Store ratingsWhat we love
- 🚀 Faithful reproduction of HP42S
- 👍 Identical to physical calculator
- 👍 Runs all original programs
- 👍 Convenient to have on phone
- 👍 Haptic feedback on button presses
Room to improve
- 🐛 Screen not filling entire display on newer devices
- 🔇 Configurable key click sound missing
- 🔇 Lack of loud click sound feedback
Bugs and requests
PCalc Lite
Reported bugs
3 issues- Calculations sometimes produce unexpected results
- Upside-down text censorship feature is problematic
- Purchased features not always accessible on Apple Watch
Requested features
4 requests- Add option to display thousands separators
- Implement a history function to review past calculations
- Provide more customization options for the widget
- Add support for sexagesimal angle input and conversion
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 Lite
- Theme Pack$0.99
- Power User Pack$0.99
- Multiple Line Pack$0.99
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- Conversion Pack$0.99
- Small Tip$0.99
- Medium Tip$1.99
- Programmer Pack$2.99
- Engineer Pack$2.99
- Large Tip$4.99
- Complete Pack$9.99
Free42
No in-app purchases
