# Engineer's Unit Converter vs HydroCalc

The clearest difference is ads: HydroCalc at none against Engineer's Unit Converter's shown. Engineer's Unit Converter's advantage is update cadence (monthly vs every 2 months). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Both are free to download. Engineer's Unit Converter sells 1 one-off in-app purchase and HydroCalc sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

Engineer's Unit Converter ships an update monthly, HydroCalc every 2 months. The most recent releases landed on October 26, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Engineer's Unit Converter | HydroCalc |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Monthly** | Every 2 months |
| Size | 7 MB | 1 MB |
| Requires iOS | 18.0 | **17.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Jose Gerardo Palma Duran](https://appshunter.io/developer/1873843788) | [Piotr Kaminski](https://appshunter.io/developer/6799375980) |

## What reviewers say

### Engineer's Unit Converter

[App page](https://appshunter.io/ios/app/engineers-unit-converter/id6758744042)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads | $0.99 | one-time |


### HydroCalc

[App page](https://appshunter.io/ios/app/hydrocalc-heating-and-flow/id6801788464)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| HydroCalc Pro | $3.99 | one-time |


## Frequently asked questions

### Is Engineer's Unit Converter free?

Engineer's Unit Converter is free to download, with in-app purchases available.

### Is HydroCalc free?

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

### Do Engineer's Unit Converter or HydroCalc have ads?

Engineer's Unit Converter shows ads; HydroCalc does not.

### Which is updated more often, Engineer's Unit Converter or HydroCalc?

Engineer's Unit Converter ships an update monthly, and HydroCalc every 2 months. Most recently, Engineer's Unit Converter was updated on October 26, 2026 and HydroCalc 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.*