# Hydraulic vs O

The clearest difference is in-app purchases: O at none against Hydraulic's 2. Hydraulic's advantage is update cadence (every 6 weeks vs every 13 months) and device support (3 vs 1). On price, ads and iOS requirement there is nothing between them.

Both are free to download. Hydraulic sells 2 one-off in-app purchases. O asks for nothing beyond the download.

Hydraulic ships an update every 6 weeks, O every 13 months. The most recent releases landed on November 1, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | Hydraulic | O |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.1 (17 ratings)](https://appshunter.io/ios/app/hydraulic-calculator/id612615039/reviews)** | — |
| Number of ratings | **17** | — |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 6 weeks** | Every 13 months |
| Monetization | Free with in-app purchases | — |
| Size | 24 MB | 5 MB |
| Requires iOS | **15.1** | 16.2 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Zanthic Automation Inc.](https://appshunter.io/developer/574695320) | [AppBakkers BV](https://appshunter.io/developer/1104913401) |

## What reviewers say

### Hydraulic

[App page](https://appshunter.io/ios/app/hydraulic-calculator/id612615039)

Perform essential hydraulic calculations for cylinders, pumps, and fluid lines. Solve for forces, speeds, torque, power, and pressure drop. Supports metric and imperial units, with advanced features unlocked via in-app purchase.

**Highlights:** Cylinder force and speed calculations, Pump displacement, flow, and pressure calculations, Hydraulic line fluid velocity and pressure drop, Orifice flow and pressure calculations, Speed, torque, and power calculations, Metric and imperial unit support, Copy results to clipboard

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Version | $7.99 | one-time |
| Pro Version | $7.99 | one-time |


### O

[App page](https://appshunter.io/ios/app/o-ringeu/id6450456605)

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Hydraulic free?

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

### Is O free?

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

### Do Hydraulic or O have ads?

Neither Hydraulic nor O shows ads.

### Which is updated more often, Hydraulic or O?

Hydraulic ships an update every 6 weeks, and O every 13 months. Most recently, Hydraulic was updated on November 1, 2026 and O on November 3, 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.*