# Hydraulic Engineer vs Hydraulic Power Unit

The clearest difference is price: Hydraulic Power Unit at Free against Hydraulic Engineer's $4.99. Hydraulic Power Unit also leads on in-app purchases (none vs 1) and iOS requirement (6.0 vs 18.6). Hydraulic Engineer's advantage is update cadence (every 6 months vs every 37 months). On ads and device support there is nothing between them.

Hydraulic Power Unit is free to download; Hydraulic Engineer costs $4.99 up front. Hydraulic Engineer sells 1 one-off in-app purchase. Hydraulic Power Unit asks for nothing beyond the download.

Hydraulic Engineer ships an update every 6 months, Hydraulic Power Unit every 37 months. The most recent releases landed on October 6, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | Hydraulic Engineer | Hydraulic Power Unit |
| --- | --- | --- |
| Price | $4.99 | **Free** |
| Rating | **[4.0 (1 ratings)](https://appshunter.io/ios/app/hydraulic-engineer/id410465591/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 25.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 6 months** | Every 37 months |
| Monetization | Paid | — |
| Size | 19 MB | 4 MB |
| Requires iOS | 18.6 | **6.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Historycentral.com](https://appshunter.io/developer/1744330560) | [Zanthic Automation Inc.](https://appshunter.io/developer/574695320) |

## What reviewers say

### Hydraulic Engineer

[App page](https://appshunter.io/ios/app/hydraulic-engineer/id410465591)

This comprehensive calculator app offers over 1,000 hydraulic engineering formulas across 13 categories. It includes temperature conversions, reference tables, and the ability to save and share calculations. Works offline and supports both US Customary and SI Metric units.

**Highlights:** Over 1,000 hydraulic formulas, 13 specialized calculator categories, Temperature scale converters, Professional reference tables, Save and share calculations, Works offline, US Customary and SI Metric units

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

**In-app purchases (1)**

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


### Hydraulic Power Unit

[App page](https://appshunter.io/ios/app/hydraulic-power-unit/id608111471)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Hydraulic Engineer free?

Hydraulic Engineer costs $4.99, and also offers in-app purchases.

### Is Hydraulic Power Unit free?

Hydraulic Power Unit is free to download, with no in-app purchases.

### Do Hydraulic Engineer or Hydraulic Power Unit have ads?

Neither Hydraulic Engineer nor Hydraulic Power Unit shows ads.

### Which is updated more often, Hydraulic Engineer or Hydraulic Power Unit?

Hydraulic Engineer ships an update every 6 months, and Hydraulic Power Unit every 37 months. Most recently, Hydraulic Engineer was updated on October 6, 2026 and Hydraulic Power Unit on October 5, 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.*