# 9toFast vs Atomic Fast

The clearest difference is ads: Atomic Fast at none against 9toFast's shown. Atomic Fast also leads on update cadence (every 4 days vs fortnightly). 9toFast's advantage is iOS requirement (15.1 vs 18.0). On price, in-app purchases and device support there is nothing between them.

Both are free to download. 9toFast sells 3 in-app purchases, starting at $0.99 per month and Atomic Fast sells 3 in-app purchases, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.

9toFast ships an update fortnightly, Atomic Fast every 4 days. The most recent releases landed on October 30, 2026 and November 5, 2026 respectively.

## The numbers

| Metric | 9toFast | Atomic Fast |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (31 ratings)](https://appshunter.io/ios/app/atomic-fast-fasting-and-diet/id6763870543/reviews)** |
| Number of ratings | — | **31** |
| Positive reviews | — | 96.3% of reviews |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | Fortnightly | **Every 4 days** |
| Monetization | — | Freemium |
| Size | 47 MB | 22 MB |
| Requires iOS | **15.1** | 18.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Apple Watch |
| Age rating | 4+ | 4+ |
| Developer | [Esther Yekini](https://appshunter.io/developer/1847063956) | [Startise](https://appshunter.io/developer/1895534080) |

## What reviewers say

### 9toFast

[App page](https://appshunter.io/ios/app/9tofast/id6754204142)

**Features:** macOS Compatibility

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Monthly | $0.99 | per month |
| Premium Yearly | $9.99 | per year |
| Premium Lifetime | $19.99 | one-time |


### Atomic Fast

[App page](https://appshunter.io/ios/app/atomic-fast-fasting-and-diet/id6763870543)

This app combines intermittent fasting with AI-powered calorie and macro tracking. It analyzes your eating patterns, hydration, sleep, and activity to provide metabolic insights and a daily readiness score. Seamlessly integrates with Apple Health for a holistic view of your well-being.

**Highlights:** AI calorie and macro estimation from photos, Intermittent fasting timer with metabolic phases, Break-fast meal scoring and suggestions, Connects meals and fasts for holistic insights, Daily readiness score based on health signals, Apple Health and Apple Watch integration

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Atomic+ Monthly | $4.99 | per month |
| Atomic+ Annual | $29.99 | per year |
| Atomic+ Lifetime | $59.99 | one-time |


## Frequently asked questions

### Is 9toFast free?

9toFast is free to download, with in-app purchases available.

### Is Atomic Fast free?

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

### Do 9toFast or Atomic Fast have ads?

9toFast shows ads; Atomic Fast does not.

### Which is updated more often, 9toFast or Atomic Fast?

9toFast ships an update fortnightly, and Atomic Fast every 4 days. Most recently, 9toFast was updated on October 30, 2026 and Atomic Fast on November 5, 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.*