Free42 vs Convex Programmer's Calculator
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
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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.
Convex Programmer's Calculator
Convert numbers between hexadecimal, decimal, octal, and binary. Perform byte flips, bit shifts, and calculate two's complement. Features bit indicators and word grouping for improved binary readability.
- Number base conversion
- Two's complement calculation
- Byte flipping for endianness
- Left and right bit shifting
- Binary readability enhancements
- Copy, paste, and clear functionality
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Easily convert between hexadecimal, decimal, octal, and binary. Calculate the two's complement of any number. Flip a number's bytes to switch its endianness. Bit-shift left and right. Bit indicators and word grouping make binary easier to read. Tap the number to copy, paste, and clear. Swipe left or right on the number to backspace.
Screenshots
Verdict
The clearest difference is update cadence: Free42 at every 9 days against Convex Programmer's Calculator's every 8 months. Free42 also leads on review sentiment (94% vs 67%) and ratings volume (284 vs 6). On price, rating, ads and in-app purchases 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.
On the App Store both sit at effectively the same score — 4.8 for Free42 against 4.7 for Convex Programmer's Calculator. That said, the two scores are not equally well evidenced: Free42 has 284 ratings behind it against 6, so its average is the more settled of the two. Written reviews are what separate them: 94% of Free42's written reviews are positive against 67% of Convex Programmer's Calculator's.
Free42 ships an update every 9 days, Convex Programmer's Calculator every 8 months. The most recent releases landed on October 18, 2026 and September 27, 2026 respectively.
| Parameter | Free42 | Convex Programmer's Calculator |
|---|---|---|
| Price | Free | Free |
| Rating | 4.8 (284 ratings) — better | 4.7 (6 ratings) |
| Positive reviews | 94.4% of reviews — better | 66.7% of reviews |
| Number of ratings | 284 — better | 6 |
| Update frequency | Every 9 days — better | Every 8 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 15.0 — better | 16.0 |
| Further details — not scored | ||
| Size | 9 MB | 0 MB |
| Age rating | 4+ | 4+ |
| Developer | Thomas Okken | Matthew Daigle |
Customer experience
Free42
Convex Programmer's Calculator
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
Convex Programmer's Calculator
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Free42
No in-app purchases
Convex Programmer's Calculator
No in-app purchases
Questions
Is Free42 free?
Is Convex Programmer's Calculator free?
Which has better reviews, Free42 or Convex Programmer's Calculator?
Do Free42 or Convex Programmer's Calculator have ads?
Which is updated more often, Free42 or Convex Programmer's Calculator?
Other comparisons
