# Hidden calc vs Unit Eater

The clearest difference is in-app purchases: Hidden calc at none against Unit Eater's 2. Unit Eater's advantage is ads (none vs shown) and iOS requirement (12.0 vs 15.8.3). On price, update cadence and device support there is nothing between them.

Both are free to download. Unit Eater sells 2 in-app purchases, starting at $0.99 per month. Hidden calc asks for nothing beyond the download.

Both ship on a similar rhythm, roughly every 2 weeks. The most recent releases landed on September 24, 2026 and September 30, 2026 respectively.

## The numbers

| Metric | Hidden calc | Unit Eater |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 2 weeks | Every 2 weeks |
| Monetization | — | Free with in-app purchases |
| Size | 35 MB | 65 MB |
| Requires iOS | 15.8.3 | **12.0** |
| Devices | iPhone, iPad, iPod | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Hideaki Uchikoshi](https://appshunter.io/developer/1559575002) | [Tom Leon Schmidt](https://appshunter.io/developer/1634212175) |

## What reviewers say

### Hidden calc

[App page](https://appshunter.io/ios/app/hidden-calc/id6502871727)

**Features:** macOS Compatibility

**In-app purchases:** none


### Unit Eater

[App page](https://appshunter.io/ios/app/unit-eater/id6742549723)

This utility app functions as a powerful calculator that handles unit conversions and calculations. It supports a vast array of predefined units and allows users to define their own, making it ideal for scientific and academic tasks. Features include a calculation history, customizable results, and dark mode.

**Highlights:** Unit conversion and calculation, Custom unit definition, Extensive unit library, Calculation history, Customizable result format, Dark mode

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium - Monthly | $0.99 | per month |
| Premium - Pay once | $3.99 | one-time |


## Frequently asked questions

### Is Hidden calc free?

Hidden calc is free to download, with no in-app purchases.

### Is Unit Eater free?

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

### Do Hidden calc or Unit Eater have ads?

Hidden calc shows ads; Unit Eater does not.

### Which is updated more often, Hidden calc or Unit Eater?

Hidden calc ships an update every 2 weeks, and Unit Eater every 2 weeks. Most recently, Hidden calc was updated on September 24, 2026 and Unit Eater on September 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.*