# Janus Calculator vs WP 31s

The clearest difference is rating: WP 31s at 4.9 against Janus Calculator's 2.0. WP 31s also leads on update cadence (every 10 months vs every 45 months) and review sentiment (100% vs 83%). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

WP 31s holds the better App Store score, 4.9 against 2.0. That said, the two scores are not equally well evidenced: WP 31s has 15 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 83% of Janus Calculator's written reviews are positive against 100% of WP 31s's.

Janus Calculator ships an update every 45 months, WP 31s every 10 months. The most recent releases landed on October 21, 2026 and October 11, 2026 respectively.

## The numbers

| Metric | Janus Calculator | WP 31s |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [2.0 (1 ratings)](https://appshunter.io/ios/app/janus-calculator/id373378721/reviews) | **[4.9 (15 ratings)](https://appshunter.io/ios/app/wp-31s/id973621300/reviews)** |
| Number of ratings | 1 | **15** |
| Positive reviews | 83.3% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 45 months | **Every 10 months** |
| Monetization | Free | Free |
| Size | 1 MB | 16 MB |
| Requires iOS | 26.2 | **12.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Geoffrey Domm](https://appshunter.io/developer/373378724) | [Pascal Meheut](https://appshunter.io/developer/620255097) |

## What reviewers say

### Janus Calculator

[App page](https://appshunter.io/ios/app/janus-calculator/id373378721)

This app offers a unique dual-calculator interface, supporting both standard and Reverse Polish Notation. It features programmable functions, extensive scientific and financial tools, and includes physical constants and an advanced option calculator.

**Highlights:** Dual calculator interface (Standard and RPN), Programmable functions, Finance and scientific functions, Physical constants, Black-Scholes option calculator, Implied value calculation

**Features:** macOS Compatibility

**In-app purchases:** none


### WP 31s

[App page](https://appshunter.io/ios/app/wp-31s/id973621300)

This app emulates a classic RPN scientific calculator, offering a rich function set for daily use with a simplified interface. It's based on the more complex WP 34s but is designed for easier operation.

**Highlights:** RPN scientific calculator emulation, Rich function set, Simplified, less cluttered keyboard, Based on WP 34s, Available on iOS

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Janus Calculator free?

Janus Calculator is free to download, with no in-app purchases.

### Is WP 31s free?

WP 31s is free to download, with no in-app purchases.

### Which has better reviews, Janus Calculator or WP 31s?

WP 31s is rated higher. Janus Calculator averages 2.0 out of 5 from 1 ratings, while WP 31s averages 4.9 from 15 ratings.

### Do Janus Calculator or WP 31s have ads?

Neither Janus Calculator nor WP 31s shows ads.

### Which is updated more often, Janus Calculator or WP 31s?

Janus Calculator ships an update every 45 months, and WP 31s every 10 months. Most recently, Janus Calculator was updated on October 21, 2026 and WP 31s on October 11, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*