# Engine Calculator Plus vs Planetary Gear Calculator

The clearest difference is rating: Planetary Gear Calculator at 4.7 against Engine Calculator Plus's 4.0. Planetary Gear Calculator also leads on review sentiment (50% vs 13%) and ratings volume (6 vs 1). Engine Calculator Plus's advantage is chart position (#183 vs unranked) and price ($2.99 vs $3.99). On update cadence, ads, in-app purchases and monetization model there is nothing between them.

Engine Calculator Plus costs $2.99 and Planetary Gear Calculator $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Planetary Gear Calculator holds the better App Store score, 4.7 against 4.0. That said, the two scores are not equally well evidenced: Planetary Gear Calculator has 6 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 13% of Engine Calculator Plus's written reviews are positive against 50% of Planetary Gear Calculator's.

Engine Calculator Plus ships an update every 48 months, Planetary Gear Calculator every 46 months. The most recent releases landed on September 10, 2026 and September 17, 2026 respectively.

## The numbers

| Metric | Engine Calculator Plus | Planetary Gear Calculator |
| --- | --- | --- |
| Price | **$2.99** | $3.99 |
| Rating | [4.0 (1 ratings)](https://appshunter.io/ios/app/engine-calculator-plus/id1355990764/reviews) | **[4.7 (6 ratings)](https://appshunter.io/ios/app/planetary-gear-calculator/id1618146516/reviews)** |
| Number of ratings | 1 | **6** |
| Positive reviews | 12.5% of reviews | **50.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 48 months | **Every 46 months** |
| Monetization | Paid | Paid |
| Best chart rank | **#183** | — |
| Size | 2 MB | 1 MB |
| Requires iOS | 13 | 13 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Nitrio](https://appshunter.io/developer/321121189) | [Heng Jia Liang](https://appshunter.io/developer/1532000635) |

## What reviewers say

### Engine Calculator Plus

[App page](https://appshunter.io/ios/app/engine-calculator-plus/id1355990764)

**Currently charting:** #183 Top Paid · Productivity (US App Store)

Calculate engine specifications for various car and plane engines, including displacement, compression ratio, and horsepower. Supports metric and imperial systems with a user-friendly interface and 3D engine visualization.

**Highlights:** Engine displacement calculation, Compression ratio calculation, Horsepower estimation, Metric and Imperial support, 3D engine display, Copyable results

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

**In-app purchases:** none


### Planetary Gear Calculator

[App page](https://appshunter.io/ios/app/planetary-gear-calculator/id1618146516)

Calculate gear teeth and speed for planetary gear systems. Quickly simulate how these systems work on the fly, ideal for DIYers designing their own systems before 3D printing. Understand the formulas and components of epicyclic gear systems.

**Highlights:** Calculate gear teeth, Calculate gear speed, Simulate planetary gear systems, Design custom gear systems, Preview system functionality, Understand gear formulas

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

**In-app purchases:** none


## Frequently asked questions

### Is Engine Calculator Plus free?

Engine Calculator Plus costs $2.99, with no in-app purchases.

### Is Planetary Gear Calculator free?

Planetary Gear Calculator costs $3.99, with no in-app purchases.

### Which has better reviews, Engine Calculator Plus or Planetary Gear Calculator?

Planetary Gear Calculator is rated higher. Engine Calculator Plus averages 4.0 out of 5 from 1 ratings, while Planetary Gear Calculator averages 4.7 from 6 ratings.

### Do Engine Calculator Plus or Planetary Gear Calculator have ads?

Neither Engine Calculator Plus nor Planetary Gear Calculator shows ads.

### Which is updated more often, Engine Calculator Plus or Planetary Gear Calculator?

Engine Calculator Plus ships an update every 48 months, and Planetary Gear Calculator every 46 months. Most recently, Engine Calculator Plus was updated on September 10, 2026 and Planetary Gear Calculator on September 17, 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.*