Comparison

Gear Calculator Plus vs SDG Rotor

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Gear Calculator Plus

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
Read full description

Gear Ratio Speed Calculator. With the gear ratios of the transmission and differential, and the size of the tires, it becomes possible to calculate the speed of the car for a particular gear at a particular engine RPM. Features: Calculate theoretical speed for a car for each of its gear ratios. Calculate travel distance for each engine revolution. Use maximum RPM to figure top speed for each gear. Metric or Imperial units for selection. Universal app for both iPhone and iPad. Axle ratio are similar as Final Drive Ratio. If a car has less than 6 gears, only enter the ratios that apply. Note that you will get unreal speeds for overdrive gears. This is because in reality top speed is physically limited by it power or by aerodynamic drag. Thanks for your support and do visit nitrio.com for more apps for your iOS devices.

About

SDG Rotor

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
Read full description

SDG Motorsports Presents: The Ultimate IHI Supercharger Tool Brought to you by SDG Motorsports, this app is the essential companion for Hellcat, Redeye, Trackhawk, Hellephant, and Demon enthusiasts. Guarantee the safety of your supercharger rotor RPM with our precision tool designed for the high-performance vehicle owner. With SDG Motorsports, you get more than just an app; you get a partner in performance and safety. Why SDG Motorsports? • Expertise in Performance: Leveraging SDG Motorsports deep understanding of high-performance vehicles, our app provides unparalleled accuracy in supercharger safety assessments. • User-Friendly Design: Developed by the experts at SDG Motorsports, this app allows you to easily input your supercharger details and engine RPM, offering safety checks in an instant. • Global Standards: No matter where you tune from, SDG Motorsports ensures that our app supports a broad spectrum of units and standards for worldwide accessibility. Your Safety, Our Priority With SDG Motorsports, stay confident in your vehicle’s performance and safety. Download today to ensure your supercharger setup is not just powerful, but also safe. Disclaimer: While SDG Motorsports strives to provide accurate and up-to-date information through our Supercharger Safety Tool, the nature of high-performance vehicles and the variability of modifications mean outcomes can vary widely. As such, SDG Motorsports cannot be held responsible for any damage, loss, or injury resulting from the use of this app. Users are encouraged to proceed with caution and consult with professional tuners or technicians when making significant modifications to their vehicles. This app is intended as a guide only, and reliance on its output is at the user's own risk.

Screenshots

Gear Calculator Plus4 screens
SDG Rotor4 screens

Verdict

The call

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.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

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.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard7 real differences · 3 level
Gear Calculator Plus versus SDG Rotor: the parameters behind the verdict, then further details
ParameterGear Calculator PlusSDG Rotor
Price$2.99Free — better
Rating3.6 (5 ratings)5.0 (1 ratings) — better
Positive reviews0.0% of reviews100.0% of reviews — better
Number of ratings5 — better1
Update frequencyEvery 29 monthsEvery 2 days — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS13 — better15.6
Further details — not scored
Size1 MB46 MB
Age rating4++17
DeveloperNitrioStephan Monette

Customer experience

Gear Calculator Plus

All ratings5 ratings
Positive60.0%
Neutral20.0%
Negative20.0%
Written reviews2 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

SDG Rotor

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Gear Calculator Plus

No in-app purchases

None

SDG Rotor

No in-app purchases

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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