Complex RPN Calculator vs ThetaCalc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Complex RPN Calculator
This scientific calculator utilizes a four-level stack and natively handles complex numbers. It allows users to input and view numbers in both polar and rectangular formats, remembering its state and offering 10 memory locations.
- Complex number support
- Four-level stack
- Polar and rectangular formats
- State persistence
- 10 memory locations
- Scientific calculations
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Complex RPN Calculator is a scientific RPN calculator with a four stack whose native number is complex. You can view and enter numbers in both polar and rectangular formats. Complex RPN remembers its state between usages and has 10 memory locations.
ThetaCalc
This utility app provides a Reverse Polish Notation (RPN) calculator. Users can extend its functionality by programming custom functions and equations using JavaScript.
- Reverse Polish Notation (RPN) calculator
- User-programmable functions
- JavaScript equation support
- Extensible functionality
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ThetaCalc is a RPN (Reverse Polish Notation) calculator which can be extended by functions and equations programmed by the user in JavaScript.
Screenshots
Verdict
The clearest difference is review sentiment: ThetaCalc at 100% against Complex RPN Calculator's 52%. ThetaCalc also leads on rating (4.3 vs 3.8). Complex RPN Calculator's advantage is ratings volume (22 vs 4). On price, update cadence, 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.
ThetaCalc holds the better App Store score, 4.3 against 3.8. That said, the two scores are not equally well evidenced: Complex RPN Calculator has 22 ratings behind it against 4, so its average is the more settled of the two. Written reviews point the same way: 52% of Complex RPN Calculator's written reviews are positive against 100% of ThetaCalc's.
Complex RPN Calculator ships an update every 5 months, ThetaCalc every 3 months. The most recent releases landed on August 23, 2026 and June 1, 2026 respectively.
| Parameter | Complex RPN Calculator | ThetaCalc |
|---|---|---|
| Price | Free | Free |
| Rating | 3.8 (22 ratings) | 4.3 (4 ratings) — better |
| Positive reviews | 51.7% of reviews | 100.0% of reviews — better |
| Number of ratings | 22 — better | 4 |
| Update frequency | Every 5 months | Every 3 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 16.4 — better | 17.6 |
| Further details — not scored | ||
| Size | 1 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | John Coddington | Felix Stehli |
Customer experience
Complex RPN Calculator
ThetaCalc
Bugs and requests
Complex RPN Calculator
Reported bugs
6 issues- Mutes other apps when used
- Slow keyboard response after update
- X^3 calculation incorrect for large imaginary numbers
- App crashes on opening/button press (historical iOS 9 issues)
- App starts upside down in landscape on iPad (historical iOS 8 issue)
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- Unreadable fonts on iPad (historical version 1.2 issue)
Requested features
24 requests- Turn off key click sound
- Customize number display
- See the stack
- Fix slow entry response
- Fix imaginary number calculation (X^3)
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- Improve SwiftUI design (less whitespace)
- Show all stack levels
- Add angle function
- Add magnitude function
- Add 'Clear X' button
- Make RAD/DEG toggle button
- Single button for Sci/Eng/Fix/Raw modes
- Add '//' (parallel) function
- Add 'Module' button
- Change 'i' to 'j' for imaginary part
- Show stack levels
- Add log2 function
- Add logGamma function
- Smaller buttons
- Add complex conjugate button
- Add real part button
- Add imaginary part button
- Add modulo function
- Make app start faster
ThetaCalc
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Complex RPN Calculator
No in-app purchases
ThetaCalc
No in-app purchases
Questions
Is Complex RPN Calculator free?
Is ThetaCalc free?
Which has better reviews, Complex RPN Calculator or ThetaCalc?
Do Complex RPN Calculator or ThetaCalc have ads?
Which is updated more often, Complex RPN Calculator or ThetaCalc?
Other comparisons
