# CalziAI vs LeanFast

The clearest difference is update cadence: LeanFast at every 4 days against CalziAI's every 10 days. CalziAI's advantage is iOS requirement (18.0 vs 26.1). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. CalziAI sells 2 in-app purchases, starting at $14.99 per month and LeanFast sells 3 in-app purchases, starting at $3.99 per month. Whichever you choose, the download price is not the number that matters.

CalziAI ships an update every 10 days, LeanFast every 4 days. Both last shipped on October 31, 2026.

## The numbers

| Metric | CalziAI | LeanFast |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 10 days | **Every 4 days** |
| Size | 194 MB | 47 MB |
| Requires iOS | **18.0** | 26.1 |
| Devices | iPhone, iPad, Apple Watch | iPhone, iPad, Apple Watch |
| Age rating | 4+ | 12+ |
| Developer | [Oscar Suazo](https://appshunter.io/developer/1834243420) | [Hajer Trabelsi](https://appshunter.io/developer/6826828505) |

## What reviewers say

### CalziAI

[App page](https://appshunter.io/ios/app/calziai/id6761741581)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Calzi PRO Monthly | $14.99 | per month |
| Calzi PRO Yearly | $99.99 | per year |


### LeanFast

[App page](https://appshunter.io/ios/app/leanfast-intermittent-fasting/id6818318288)

**Features:** macOS Compatibility, Family Sharing, Apple Watch app, iPhone Duo support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Prism Monthly | $3.99 | per month |
| Prism Yearly | $29.99 | per year |
| Prism Lifetime | $49.99 | one-time |


## Frequently asked questions

### Is CalziAI free?

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

### Is LeanFast free?

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

### Do CalziAI or LeanFast have ads?

Neither CalziAI nor LeanFast shows ads.

### Which is updated more often, CalziAI or LeanFast?

CalziAI ships an update every 10 days, and LeanFast every 4 days. Most recently, CalziAI was updated on October 31, 2026 and LeanFast on October 31, 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.*