# Numbers and Functions f/ Watch — RPN Calculator

> RPN Calculator (iPhone/iPad app by Stefan Kopp.)

- Source: https://appshunter.io/ios/app/numbers-and-functions-f-watch/id6448701785 (this page in markdown: same URL + `.md`)
- Developer: [Stefan Kopp](https://appshunter.io/developer/1575382892)
- Category: Productivity, Utilities
- Price: $0.99
- Age rating: 4+
- Requires: iOS 13.0 · 1 MB
- Languages: English
- Released: 2023-05-03
- Data updated: 2026-05-19
- User reviews in markdown: https://appshunter.io/ios/app/numbers-and-functions-f-watch/id6448701785/reviews.md

## What is Numbers and Functions f/ Watch?

Adds a wearable calculator to your watch with support for advanced math functions and complex numbers.

Functions supported:
- Basic math
- Square root, power, logarithmic functions
- Trigonometry
- Percentage
- Gamma, log-gamma
- Error function, complementary error function
- Factorials
- Random numbers
- Absolute value
- Round to integer
- Creation of complex numbers from their components (Re/Im or r/phi)
- Conjugate
- Change of notation between Re/Im and polar (r/phi)
- Basic math for complex numbers

This calculator uses postfix notation (also know as Reverse Polish notation). If you have ever used an RPN calculator (such as a classic HP calculator), you will not want to switch back. For those not familiar with RPN: enter the operands first, then select the operation. Operands are pushed on a stack and removed when applying an operation. Results are pushed back on the stack, ready for the next operation.

Various numbers styles can be selected (regular floating point, scientific notation, engineering notation).

This is a standalone watch app and does not require your iPhone to be nearby.

No in-app purchases or other hidden cost. Buy now and get future enhancements at no additional cost!


## Version history (last 1 release)

### 1.3 — 2023-05-11

This version adds a number of statistical functions (incl. gamma, log-gamma, error function, complementary error function, factorial, random).

## Apps similar to Numbers and Functions f/ Watch

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [Expressio Calculator](https://appshunter.io/ios/app/expressio-calculator/id1505070615) | — | Free | Productivity |
| [Smart Projector Control](https://appshunter.io/ios/app/smart-projector-control/id1139035542) | 2.9 (16) | Free | Productivity |
| [Infinity VPN: Unlimited Proxy](https://appshunter.io/ios/app/infinity-vpn-unlimited-proxy/id1576741102) | 4.3 (1,780) | Free | Productivity |
| [Router Utility](https://appshunter.io/ios/app/router-utility/id582215646) | 2.5 (37) | Free | Productivity |
| [eDrawings](https://appshunter.io/ios/app/edrawings/id520231936) | 2.5 (17) | $1.99 | Productivity |
| [ISL Light](https://appshunter.io/ios/app/isl-light/id427579815) | 2.4 (23) | Free | Productivity |

## More apps by Stefan Kopp

- [White Cloud Blue Sky](https://appshunter.io/ios/app/white-cloud-blue-sky/id1575382890)
- [White Cloud Blue Sky for Watch](https://appshunter.io/ios/app/white-cloud-blue-sky-for-watch/id1667460320)

All apps by Stefan Kopp: https://appshunter.io/developer/1575382892

---

*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 2026-05-19.*