# 4+2R健康日記 vs KnowKnow AI

The clearest difference is in-app purchases: 4+2R健康日記 at none against KnowKnow AI's 4. 4+2R健康日記 also leads on iOS requirement (13.0 vs 16.4). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. KnowKnow AI sells 4 in-app purchases, starting at $9.99 per month. 4+2R健康日記 asks for nothing beyond the download.

4+2R健康日記 ships an update fortnightly, KnowKnow AI every 3 weeks. The most recent releases landed on September 17, 2026 and September 16, 2026 respectively.

## The numbers

| Metric | 4+2R健康日記 | KnowKnow AI |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[3.0 (2 ratings)](https://appshunter.io/ios/app/knowknow-ai/id6748773796/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Fortnightly** | Every 3 weeks |
| Monetization | — | Freemium |
| Size | 79 MB | 104 MB |
| Requires iOS | **13.0** | 16.4 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Amortality Inc.](https://appshunter.io/developer/1797258559) | [RETOWER TECH PTE. LTD.](https://appshunter.io/developer/1827325376) |

## What reviewers say

### 4+2R健康日記

[App page](https://appshunter.io/ios/app/4-plus-2r-and/id6742175221)

**In-app purchases:** none


### KnowKnow AI

[App page](https://appshunter.io/ios/app/knowknow-ai/id6748773796)

Effortlessly track your nutrition by simply snapping a photo of your food. This AI-powered tool provides instant analysis of calorie and macronutrient content, helping you understand your dietary intake.

**Highlights:** AI-powered food analysis, Instant calorie and macro breakdown, Photo-based tracking, Nutrition insights

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| KnowKnow Plus | $9.99 | per month |
| KnowKnow Pro | $14.99 | per month |
| KnowKnow Plus Yearly | $113.99 | per year |
| KnowKnow Pro Yearly | $178.99 | per year |


## Frequently asked questions

### Is 4+2R健康日記 free?

4+2R健康日記 is free to download, with no in-app purchases.

### Is KnowKnow AI free?

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

### Do 4+2R健康日記 or KnowKnow AI have ads?

Neither 4+2R健康日記 nor KnowKnow AI shows ads.

### Which is updated more often, 4+2R健康日記 or KnowKnow AI?

4+2R健康日記 ships an update fortnightly, and KnowKnow AI every 3 weeks. Most recently, 4+2R健康日記 was updated on September 17, 2026 and KnowKnow AI on September 16, 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.*