Carat 2.01 can also show App Recommendations on iOS 9.0 through 9.3.2!

Our next release will include settings recommendations for iOS 9.3.3+. We are already collecting the data for this, so stay tuned!


Carat is the first app to generate personalized recommendations for improving your battery life. After observing your use of the device for *a week or more*, it will start to generate reports just for you. You should open the app once every day or so, with an Internet connection turned on, until you start seeing results.

Although Carat uses Location Services (thus displaying the little icon), it is NOT using your GPS and is NOT running in the background. The app uses almost no power.

** Thank you! **

Ever wondered why your battery is draining so quickly? Just install Carat, open it every few days with an Internet connection turned on so it can send data to our servers, and within a week Carat will start recommending Actions (just for you!) and even predicting the improvements you will see. Although Carat cannot measure energy use directly, it infers what apps are responsible using advanced machine learning methods.

And it's free!

As you use your device, Carat occasionally takes measurements and sends them to our backend servers in the cloud, where we apply cutting-edge algorithms to determine what steps you can take to use less energy. By collecting snippets of non-personal data from a large number of devices, Carat does not need to run continuously in the background. Nothing we collect identifies you, personally.

Carat will tell you which apps generally use a lot of energy and and those that specifically do so on your device (but not on most others). This does not make an app 'bad', but this advice can help a user improve their battery life.

== Carat Features ==

- Action List telling you how to improve your battery life and by how much
- Device information detailing exactly what data we are recording
- Reports apps that are using lots of energy and whether that is happening on other devices, too
- Detail views let you dive down into the data
- Low-overhead sampling requires almost no energy or CPU
- J-Score tells you how your battery efficiency compares to other users
- Sharing features let you post/tweet/blog about your experience; more users means more data which means better recommendations for you

Carat is under active development by a team of researchers in University of Helsinki. We are constantly making improvements, adding features, and giving you more knowledge about how your device is using energy. Remember, knowledge is power!

What's New

Version 2.013

Fixed a problem with settings.

Ratings and Reviews

4.2 out of 5

5 Ratings

5 Ratings

iPhone Fountain of Youth


I mentioned this app to a colleague who thought he would need to buy a new phone because his current phone was slowing down. I got a message later that he had made the adjustments suggested by the app and it "was like having a brand new phone."

It's not working

Carlos- As


Research takes a long time (updated)


This app is very new, very unique, and free so people should quit complaining. As with any good research project, it all starts with a good collection of data. The team at UC Berkeley has a great project running with this app so give it some time to collect data and populate suggestions for you. Considering how much this app is capable of, it's pretty amazing that they can give you suggestions after a few days. That being said, the app seems to have given me a little more battery life but still no suggestions. (It's only been two days though.) For now, I will be giving this 5 stars to help support the team. I feel a lot of people don't understand this app or are too impatient to let it run long enough to benefit them. I will re-review later this week.

This app does not work. It has been a week now and it has done nothing. It glitches and leaves GPS on constantly. My phone has been on and doing nothing for about 5 hours and the battery is now lower than 50%. This is is cool but there is obviously a problem and despite the team's readme, it does indeed use more battery and it DOES drain by constant use of GPS. I'm looking forward to a patch but until then, my rating is very low.


University of Helsinki
14.6 MB
Requires iOS 7.0 or later. Compatible with iPhone, iPad, and iPod touch.
English, Finnish
Age Rating
Rated 4+
© 2012-2016 University of Helsinki, Department of CS & UC Berkeley, AMP Lab


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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