# pHCalculation vs Chem Memo เคมี ม.4

The clearest difference is ads: pHCalculation at none against Chem Memo เคมี ม.4's shown. pHCalculation also leads on update cadence (every 5 days vs every 2 months). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Both are free to download. pHCalculation sells 5 one-off in-app purchases and Chem Memo เคมี ม.4 sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

pHCalculation ships an update every 5 days, Chem Memo เคมี ม.4 every 2 months. The most recent releases landed on October 9, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | pHCalculation | Chem Memo เคมี ม.4 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 5 days** | Every 2 months |
| Size | 2 MB | 28 MB |
| Requires iOS | 18.6 | **18.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Jatuphol Jaturapat](https://appshunter.io/developer/1788860463) | [ChatStick Company Limited](https://appshunter.io/developer/1165816085) |

## What reviewers say

### pHCalculation

[App page](https://appshunter.io/ios/app/phcalculation/id6743737030)

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Show solution | $0.99 | one-time |
| Buffer Calculator | $0.99 | one-time |
| Salt pH calculator | $0.99 | one-time |
| Reverse pH calculator | $0.99 | one-time |
| Unlock All Features. | $1.99 | one-time |


### Chem Memo เคมี ม.4

[App page](https://appshunter.io/ios/app/chem-memo-4-6/id6804657033)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock All Features | $2.99 | one-time |


## Frequently asked questions

### Is pHCalculation free?

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

### Is Chem Memo เคมี ม.4 free?

Chem Memo เคมี ม.4 is free to download, with in-app purchases available.

### Do pHCalculation or Chem Memo เคมี ม.4 have ads?

Chem Memo เคมี ม.4 shows ads; pHCalculation does not.

### Which is updated more often, pHCalculation or Chem Memo เคมี ม.4?

pHCalculation ships an update every 5 days, and Chem Memo เคมี ม.4 every 2 months. Most recently, pHCalculation was updated on October 9, 2026 and Chem Memo เคมี ม.4 on October 25, 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.*