ThetaCalc vs Calccis
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
Calccis
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Calccis is a reverse polish notation (RPN) calculator. It supports basic arithmetic, trigonometrical, logarithm and exponent calculations for real, fractional, and complex numbers. Degrees and radians can be used for trigonometrical functions. You can perform matrix calculations, too. There is an undo stack, which supports undoing and redoing the 100 latest operations. Calccis does not copy or mimic any existing physical calculators. However, the operation of the stack has been influenced by how the stack works in the 1990s Hewlett-Packard HP-48 family of calculators.
Screenshots
Verdict
The clearest difference is update cadence: Calccis at every 3 weeks against ThetaCalc's every 3 months. On price, ads, in-app purchases 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. Neither carries in-app purchases, so what you see is what you pay.
ThetaCalc ships an update every 3 months, Calccis every 3 weeks. The most recent releases landed on June 1, 2026 and September 12, 2026 respectively.
| Parameter | ThetaCalc | Calccis |
|---|---|---|
| Price | Free | Free |
| Rating | 4.3 (4 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 4 — better | — |
| Update frequency | Every 3 months | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 17.6 | 17.6 |
| Further details — not scored | ||
| Size | 1 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Felix Stehli | Jukka Aittola |
In-app purchases
ThetaCalc
No in-app purchases
Calccis
No in-app purchases
