# Gear Calculator Plus vs SDG Rotor

The clearest difference is review sentiment: SDG Rotor at 100% against Gear Calculator Plus's 0%. SDG Rotor also leads on price (Free vs $2.99) and rating (5.0 vs 3.6). Gear Calculator Plus's advantage is ratings volume (5 vs 1) and iOS requirement (13 vs 15.6). On ads, in-app purchases and device support there is nothing between them.

SDG Rotor is free to download; Gear Calculator Plus costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

SDG Rotor holds the better App Store score, 5.0 against 3.6. That said, the two scores are not equally well evidenced: Gear Calculator Plus has 5 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 0% of Gear Calculator Plus's written reviews are positive against 100% of SDG Rotor's.

Gear Calculator Plus ships an update every 29 months, SDG Rotor every 2 days. The most recent releases landed on November 2, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | Gear Calculator Plus | SDG Rotor |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | [3.6 (5 ratings)](https://appshunter.io/ios/app/gear-calculator-plus/id1094652540/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/sdg-rotor/id6480425498/reviews)** |
| Number of ratings | **5** | 1 |
| Positive reviews | 0.0% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 29 months | **Every 2 days** |
| Monetization | Paid | **Free** |
| Size | 1 MB | 46 MB |
| Requires iOS | **13** | 15.6 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | +17 |
| Developer | [Nitrio](https://appshunter.io/developer/321121189) | [Stephan Monette](https://appshunter.io/developer/1299469285) |

## What reviewers say

### Gear Calculator Plus

[App page](https://appshunter.io/ios/app/gear-calculator-plus/id1094652540)

Calculate a car's theoretical speed in any gear based on engine RPM, transmission, differential ratios, and tire size. It can also determine travel distance per engine revolution and estimate top speed for each gear. Supports both metric and imperial units.

**Highlights:** Calculate theoretical speed per gear, Calculate travel distance per engine revolution, Determine top speed for each gear, Metric or Imperial units, Universal app for iPhone and iPad

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

**In-app purchases:** none


### SDG Rotor

[App page](https://appshunter.io/ios/app/sdg-rotor/id6480425498)

This tool helps high-performance vehicle owners ensure the safety of their supercharger rotor RPM. It allows users to input supercharger details and engine RPM for instant safety checks, leveraging expert knowledge in performance vehicles.

**Highlights:** Supercharger rotor RPM safety checks, Input supercharger details and engine RPM, Instant safety assessments, Expertise in high-performance vehicles, User-friendly design, Supports global units and standards

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

**In-app purchases:** none


## Frequently asked questions

### Is Gear Calculator Plus free?

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

### Is SDG Rotor free?

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

### Which has better reviews, Gear Calculator Plus or SDG Rotor?

SDG Rotor is rated higher. Gear Calculator Plus averages 3.6 out of 5 from 5 ratings, while SDG Rotor averages 5.0 from 1 ratings.

### Do Gear Calculator Plus or SDG Rotor have ads?

Neither Gear Calculator Plus nor SDG Rotor shows ads.

### Which is updated more often, Gear Calculator Plus or SDG Rotor?

Gear Calculator Plus ships an update every 29 months, and SDG Rotor every 2 days. Most recently, Gear Calculator Plus was updated on November 2, 2026 and SDG Rotor on October 31, 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.*