# Set Theory Calculator vs Rhythm+

The clearest difference is price: Set Theory Calculator at $3.99 against Rhythm+'s $8.99. Set Theory Calculator also leads on update cadence (every 3 weeks vs every 2 months). Rhythm+'s advantage is iOS requirement (13.0 vs 26.0). On ads, in-app purchases and device support there is nothing between them.

Set Theory Calculator costs $3.99 and Rhythm+ $8.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Set Theory Calculator ships an update every 3 weeks, Rhythm+ every 2 months. The most recent releases landed on October 10, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Set Theory Calculator | Rhythm+ |
| --- | --- | --- |
| Price | **$3.99** | $8.99 |
| Rating | **[5.0 (4 ratings)](https://appshunter.io/ios/app/set-theory-calculator/id791334943/reviews)** | — |
| Number of ratings | **4** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 2 months |
| Monetization | Paid | — |
| Size | 8 MB | 24 MB |
| Requires iOS | 26.0 | **13.0** |
| Devices | iPhone | **iPhone, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [L Tomlin](https://appshunter.io/developer/791334946) | [Berserk Software AS](https://appshunter.io/developer/1475170649) |

## What reviewers say

### Set Theory Calculator

[App page](https://appshunter.io/ios/app/set-theory-calculator/id791334943)

This app analyzes musical pitch class sets using post-tonal theory. It calculates normal and prime forms, displays Forte numbers, and generates interval class vectors. Users can also transpose, invert, complement, and play sets as melodies or chords, with an included overview of set theory.

**Highlights:** Calculate Normal Form and Prime Form, Display Forte Number, Calculate interval class vector, Transpose and invert sets, Display set matrix, Sort, invert, or complement sets, Play sets as melody or chord

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Rhythm+

[App page](https://appshunter.io/ios/app/rhythm-plus/id1475170650)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Set Theory Calculator free?

Set Theory Calculator costs $3.99, with no in-app purchases.

### Is Rhythm+ free?

Rhythm+ costs $8.99, with no in-app purchases.

### Do Set Theory Calculator or Rhythm+ have ads?

Neither Set Theory Calculator nor Rhythm+ shows ads.

### Which is updated more often, Set Theory Calculator or Rhythm+?

Set Theory Calculator ships an update every 3 weeks, and Rhythm+ every 2 months. Most recently, Set Theory Calculator was updated on October 10, 2026 and Rhythm+ on October 25, 2026.

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