# HPLC Calculator vs 4DI

The clearest difference is in-app purchases: 4DI at none against HPLC Calculator's 6. 4DI also leads on ads (none vs shown) and update cadence (every 3 days vs every 5 weeks). HPLC Calculator's advantage is device support (3 vs 1) and iOS requirement (13.0 vs 18.6). On price there is nothing between them.

Both are free to download. HPLC Calculator sells 6 in-app purchases, starting at $0.59 per month. 4DI asks for nothing beyond the download.

HPLC Calculator ships an update every 5 weeks, 4DI every 3 days. The most recent releases landed on September 15, 2026 and August 30, 2026 respectively.

## The numbers

| Metric | HPLC Calculator | 4DI |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 5 weeks | **Every 3 days** |
| Size | 66 MB | 4 MB |
| Requires iOS | **13.0** | 18.6 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Youhana Mehany](https://appshunter.io/developer/1600330996) | [Robert Poetzsch](https://appshunter.io/developer/1860642630) |

## What reviewers say

### HPLC Calculator

[App page](https://appshunter.io/ios/app/hplc-calculator/id1600330994)

**Features:** macOS Compatibility

**In-app purchases (6)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads | $0.59 | per month |
| Remove Ads | $4.99 | per year |
| 50K Token Top-Up | $2.99 | one-time |
| 100K Token Top-Up | $4.99 | one-time |
| 250K Token Top-Up | $9.99 | one-time |
| 500K Token Top-Up | $12.99 | one-time |


### 4DI

[App page](https://appshunter.io/ios/app/4di-data-integrity-tool/id6760180866)

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

**In-app purchases:** none


## Frequently asked questions

### Is HPLC Calculator free?

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

### Is 4DI free?

4DI is free to download, with no in-app purchases.

### Do HPLC Calculator or 4DI have ads?

HPLC Calculator shows ads; 4DI does not.

### Which is updated more often, HPLC Calculator or 4DI?

HPLC Calculator ships an update every 5 weeks, and 4DI every 3 days. Most recently, HPLC Calculator was updated on September 15, 2026 and 4DI on August 30, 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.*