Ratio Calc!

Name: Ratio Calc!
Rating: 4.5 (25 reviews)
Author: David Mills

by David Mills

iPhone · iPad

Active Last checked 31 Jul 2026

App Store ↗

Quick verdict

What it is: Store information collected; independent summary not yet available.
At a glance: $2.99
In-app purchases

Categories and search queries

Official categories

Sports
Utilities

AppCorpus categories

Key functions

Function	Availability	Access	Scope	Evidence
In-app purchases	Yes	Limited free	—	Store published

Screens

No screenshots collected yet.

Pricing & paywalls

App Store

Price: $2.99
In-app purchases

Last verified 31 Jul 2026

Ratings & reviews

App Store

4.5 25 ratings · App Store

5/5Best roll-out calc out there
Keep it up !!!!!! Your last updated totally made my day.

Wrxmoose · 31 Jul 2026
5/5Great simple app
Does exactly what you need it to do; quickly figure out gear ratios and rollout. Saves your individual cars and their settings. Buy this app for gearing, you won't be disappointed.

DOSdaze · 31 Jul 2026
5/5Perfect!
Well done! I love the amount of cars you have in the library. Great tool!

Korelick · 31 Jul 2026
5/5Perfect!
this app is great, everything you need it to do. The car database is amazing, its so easy to get more cars added you just email in app and days later they add it. In app updates is another major plus!

Jdmpurest · 31 Jul 2026
5/5Time saver
This app allows quick and easy calculations to be made at the track when you need that little extra to beat the competition.

Subversive Coma · 31 Jul 2026

Privacy & accessibility

App Store

Privacy

Data Not Collected Developer declared

Accessibility

No accessibility labels collected yet.

Versions

App Store

4.60
-Mod 1.0 support -Mod 0.8 support -Latest database
4.70
-iPad support! -Latest database
4.80
*Bug fixes *latest database and logos
5.0
-New look and layout -Requires iOS6 and above -84 DP, Mod 0.4, Mod 0.6 pitch support
5.01
-Bug fixes (iOS 7.x) -Latest database -Performance improvements
5.02
More iOS7 bugfixes - sorry :-(
5.03
-Quick access chart buttons for saved cars now display correct pinion/spur info
5.10
-Updated for iOS8, iPhone 6, iPhone 6+ -Latest car database -iOS7 is now a minimum requirement -Bug fixes
6.0
Introducing Ratio Calc! for Apple Watch - view your cars ratio/rollout with ease. Now you can store your transponder numbers so that they're available quickly when booking in - view them either on the Apple Watch or on the Today screen (iOS8 required). If you love using Ratio Calc! please leave a review - it's greatly appreciated. Many thanks.
6.0.1
-Database update URL has now changed. This version is required to continue receiving car database updates. -Fixed a bug which hid the car notes under the keyboard if the note was more than a few lines long. Thanks Michael T for reporting this.
6.1
- Transponder store improvements - you can now save more than 3 transponder numbers - thanks to Jason H for the suggestion. ****Note:**** Please ensure you visit the transponder store part of the app to migrate your existing transponder numbers over to the new version. Until this is done they will not show in the Today widget or on the Apple Watch Glance. - iPad multitasking support for iO9 - Revised app layouts - faster navigation using tabs - Several other tweaks and improvements
6.2
-Improved car database updating - simply pull to refresh on the manufacturers screen -Quickly copy your transponder number into the clipboard -Fixed an issue with the ruler displaying incorrectly -Improved iPad Pro support
6.3
-You can now update the car database more easily -iOS10 compatibility -Latest car database included
6.3.1
- Change of support email address Enjoy your racing!
6.4
-iPhone X support -Improved Apple Watch app (watchOS 2+ required) -Now you can save motor and timing details for your saved cars -Improved displays when using larger display fonts
6.5
We've added a tip jar - the app has been kept up to date since 2011 and we've never charged for an update. Any tip will unlock the ability to change the app's colour scheme and app icon - we've even included some retro icons that may be familiar to long time users. Also in this version: -Improved watch app reliability -Transponder input form improvements -Other boring little fixes and optimisations
6.6
-Support for the latest devices and iOS -Improved the database update process to show more details -Removed the text erasing buttons on the text fields when editing notes -Moved the gear and diameter pickers up so that the results can be seen whilst changing the settings -Updated database and manufacturers -Various other little tweaks and improvements Enjoy your R/C racing!
7.0
Ratio Calc is back, modernised, and free. Please consider leaving a tip. -Easily searchable cars list -Quickly mark your favourite cars -Dark mode -Dark mode app icons -Transponder widget
7.1
-Improved charts -Updated database
7.2
-Improved data entry for pinion, spur and tyre diameters to allow faster calculations -Historic saved cars can now have their gear, spur, pitch and diameters adjusted for calculations, however changes will not yet be saved
7.3
-You can now save cars, with notes etc -Saved cars can now be amended
7.4
-Fixed an issue with the charts disappearing for saved cars - thanks Ali! -Pull to refresh on the Manufacturers list now updates the car database
7.4.1
-Improved the app layout when landscape on the largest phones
7.5
-Improved search results now show the correct number of results -Updated for iOS 26 -Latest version of the car database
7.5.1 · 11 Nov 2025
-Car search now works by manufacturer name as well -Fixed some manufacturer logo display issues -Improved the database update process -Some updated manufacturer logos -Fixed an issue with Zen Racing no longer showing

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Alternatives

Gear Ratio Calculator 2 — Same category + similar ratings

Availability by market

Data quality & evidence

Page completeness: Live store listing
Last verified: 31 Jul 2026
Sources: App Store

Independent summary has not been published yet.
Screenshots: not yet collected

Report a correction

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Example prompt

Compare Ratio Calc! with Gear Ratio Calculator 2.

View JSON

GET /api/v3/apps/436311293

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      "app_id": 6449957065,
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