# Calccis — A RPN calculator

> A RPN calculator (iPhone/iPad app by Jukka Aittola.)

- Source: https://appshunter.io/ios/app/calccis/id6446233205 (this page in markdown: same URL + `.md`)
- Developer: [Jukka Aittola](https://appshunter.io/developer/1676073314)
- Category: Utilities
- Price: Free
- Age rating: 4+
- Requires: iOS 17.6 · 1 MB
- Languages: American English, Finnish
- Released: 2023-04-21
- Data updated: 2026-05-16
- User reviews in markdown: https://appshunter.io/ios/app/calccis/id6446233205/reviews.md

## What is Calccis?

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.


## Version history (last 5 releases)

### 1.1.1 — 2025-12-15

Some minor bug fixes. Lots of internal improvements and refactoring to support further development.

### 1.1.0 — 2025-05-26

The main new feature in this version is support for matrixes.

Calccis can perform the following matrix calculations:
- addition
- subtraction
- multiplication (also scalar * matrix)
- inverse (1/x)
- determinant
- transposition
- dot product for vectors

Inputting matrixes is somewhat limited. It is not possible to enter complex or rational values into the matrixes, yet.

Other improvements include, among others:
- Scientific formatting of numbers (-1.24E-4) works more nicely.
- Multiplications and divisions of complex numbers that only have a real or imaginary part use cartesian values for calculation. This change avoids small numerical errors caused by converting the values to polar format, and the use of trigonometrical functions.
- Changing the angle unit (Deg -> Rad or vice versa) updates the angle units of complex values in the stack.
- There is an edit function, which copies the selected (or topmost) value of the stack to the edit buffer. This feature is currently available for matrixes and plain numerical values only, not for complex numbers or fractions.

### 1.0.8 — 2025-05-06

Copying and pasting values from Calccis has been improved. It's now possible to paste back all values, including fractions and complex numbers, that have been displayed in Calccis. It's possible to copy any value that is currently shown in the stack.

In addition, several bugs have been fixed, including:
- calculating the inverse of an integer now returns a floating point value and not a fraction (i.e., calculating 1/x of 5 returns 0.2, not 1/5).
- complex numbers with a negative imaginary part should now always be formatted correctly. In some situations, they were formatted like 3 - -2i.
- it is no longer possible to input a complex number in polar format with a negative absolute value.

### 1.0.7 — 2025-04-15

Simple calculations of factorials (n!), permutations (nPr), and combinations (nCr) have been added.

### 1.0.6 — 2025-04-01

Improve the calculations with fractional numbers. Fractions can now be used in complex numbers, and simple calculations with complex numbers containing fractions work nicely.

## Apps similar to Calccis

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [Dozecal](https://appshunter.io/ios/app/dozecal/id1521160089) | 4.0 (4) | Free | Utilities |
| [Time Jump - Date Calculator](https://appshunter.io/ios/app/time-jump-date-calculator/id949287666) | 5.0 (5) | $2.99 | Utilities |
| [Calculator for Complex Field](https://appshunter.io/ios/app/calculator-for-complex-field/id6502463794) | 5.0 (4) | Free | Utilities |
| [SwiftRPN](https://appshunter.io/ios/app/swiftrpn/id6470951024) | — | Free | Utilities |
| [RPNu](https://appshunter.io/ios/app/rpnu/id1195709318) | — | Free | Utilities |
| [ThetaCalc](https://appshunter.io/ios/app/thetacalc/id1521614636) | 4.3 (4) | Free | Utilities |

---

*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-05-16.*