# SimpleFFT vs Contour Detection

The clearest difference is in-app purchases: Contour Detection at none against SimpleFFT's 1. Contour Detection also leads on update cadence (fortnightly vs every 18 months). SimpleFFT's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 17.7.2). On price and ads there is nothing between them.

Both are free to download. SimpleFFT sells 1 one-off in-app purchase. Contour Detection asks for nothing beyond the download.

SimpleFFT ships an update every 18 months, Contour Detection fortnightly. The most recent releases landed on October 10, 2026 and September 30, 2026 respectively.

## The numbers

| Metric | SimpleFFT | Contour Detection |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | Yes | Yes |
| Update frequency | Every 18 months | **Fortnightly** |
| Size | 5 MB | 36 MB |
| Requires iOS | **15.0** | 17.7.2 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [HIROFUMI MARUO](https://appshunter.io/developer/667820705) | [Hideaki Uchikoshi](https://appshunter.io/developer/1559575002) |

## What reviewers say

### SimpleFFT

[App page](https://appshunter.io/ios/app/simplefft/id1239257017)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Functions | $0.49 | one-time |


### Contour Detection

[App page](https://appshunter.io/ios/app/contour-detection/id6511213082)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is SimpleFFT free?

SimpleFFT is free to download, with in-app purchases available.

### Is Contour Detection free?

Contour Detection is free to download, with no in-app purchases.

### Do SimpleFFT or Contour Detection have ads?

Both SimpleFFT and Contour Detection show ads.

### Which is updated more often, SimpleFFT or Contour Detection?

SimpleFFT ships an update every 18 months, and Contour Detection fortnightly. Most recently, SimpleFFT was updated on October 10, 2026 and Contour Detection on September 30, 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.*