# 16 vs Mantis

The clearest difference is in-app purchases: Mantis at none against 16's 3. Mantis also leads on update cadence (every 3 days vs every 9 days). 16's advantage is iOS requirement (15.0 vs 17.0). On price, ads and device support there is nothing between them.

Both are free to download. 16 sells 3 in-app purchases, starting at $1.99 per month. Mantis asks for nothing beyond the download.

16 ships an update every 9 days, Mantis every 3 days. Both last shipped on October 24, 2026.

## The numbers

| Metric | 16 | Mantis |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (54 ratings)](https://appshunter.io/ios/app/168-intermittent-fasting/id6708227128/reviews)** | — |
| Number of ratings | **54** | — |
| Positive reviews | 77.8% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 9 days | **Every 3 days** |
| Monetization | Free with in-app purchases | — |
| Size | 6 MB | 28 MB |
| Requires iOS | **15.0** | 17.0 |
| Devices | iPhone, iPod | iPhone, Apple Watch |
| Age rating | 4+ | 12+ |
| Developer | [Heze Refresh Network Technology Co., Ltd](https://appshunter.io/developer/1690178793) | [Mikhail Kurbatov](https://appshunter.io/developer/6812049805) |

## What reviewers say

### 16

[App page](https://appshunter.io/ios/app/168-intermittent-fasting/id6708227128)

This app helps users adopt intermittent fasting by tracking fasting periods, weight changes, and daily water intake. It integrates with Apple Health to import exercise data, providing insights into daily activity alongside dietary progress.

**Highlights:** Fasting tracking, Weight tracking, Water intake tracking, HealthKit integration, Fasting progress visualization

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro (Monthly) | $1.99 | per month |
| Pro (Yearly) | $8.99 | per year |
| Pro (Lifetime) | $17.99 | one-time |


### Mantis

[App page](https://appshunter.io/ios/app/mantis-smart-workouts/id6812049803)

**Features:** Apple Watch app

**In-app purchases:** none


## Frequently asked questions

### Is 16 free?

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

### Is Mantis free?

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

### Do 16 or Mantis have ads?

Neither 16 nor Mantis shows ads.

### Which is updated more often, 16 or Mantis?

16 ships an update every 9 days, and Mantis every 3 days. Most recently, 16 was updated on October 24, 2026 and Mantis on October 24, 2026.

---

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