# III vs 化学大师

The clearest difference is price: 化学大师 at Free against III's $2.99. 化学大师 also leads on update cadence (every 5 months vs every 17 months). III's advantage is in-app purchases (none vs 10). On ads, device support and iOS requirement there is nothing between them.

化学大师 is free to download; III costs $2.99 up front. 化学大师 sells 10 one-off in-app purchases. III asks for nothing beyond the download.

III ships an update every 17 months, 化学大师 every 5 months. The most recent releases landed on October 30, 2026 and October 26, 2026 respectively.

## The numbers

| Metric | III | 化学大师 |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | **[4.0 (1 ratings)](https://appshunter.io/ios/app/iii-v-comp/id475184953/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 17 months | **Every 5 months** |
| Monetization | Paid | — |
| Size | 10 MB | 40 MB |
| Requires iOS | **11.0** | 12.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 9+ |
| Developer | [Takuya Ishikawa](https://appshunter.io/developer/468311118) | [Hangzhou WuJie Network Technology Co.,Ltd.](https://appshunter.io/developer/850948888) |

## What reviewers say

### III

[App page](https://appshunter.io/ios/app/iii-v-comp/id475184953)

Calculate material properties for III-V compound semiconductors like AlGaInAsP. It determines compositions, lattice constant, strain, bandgap, and effective masses for InP or GaAs substrates.

**Highlights:** III-V compound semiconductor calculations, Material property determination, Composition calculation (x, y, z), Lattice constant and strain analysis, Bandgap and effective mass calculation, Supports InP and GaAs substrates

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

**In-app purchases:** none


### 化学大师

[App page](https://appshunter.io/ios/app/id1221293112)

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 初中数学一年会员 | $124.99 | one-time |
| 初中物理一年会员 | $124.99 | one-time |
| 初中化学一年会员 | $124.99 | one-time |
| 初中语文一年会员 | $124.99 | one-time |
| 小学科学一年会员 | $124.99 | one-time |
| 初中数理化半年会员 | $124.99 | one-time |
| 高中数学一年会员 | $199.99 | one-time |
| 高中化学一年会员 | $199.99 | one-time |
| 高中物理一年会员 | $199.99 | one-time |
| 高中数理化一年会员 | $399.99 | one-time |


## Frequently asked questions

### Is III free?

III costs $2.99, with no in-app purchases.

### Is 化学大师 free?

化学大师 is free to download, with in-app purchases available.

### Do III or 化学大师 have ads?

Neither III nor 化学大师 shows ads.

### Which is updated more often, III or 化学大师?

III ships an update every 17 months, and 化学大师 every 5 months. Most recently, III was updated on October 30, 2026 and 化学大师 on October 26, 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.*