Hi Sneha Shanbhag,

Normally, the use case for CountDownTimer only used during your app is running foreground.

I don’t think there is a significant battery drain. It would still depend on your case. There is certainly other stuff that will drain more battery like animation, video and etc.

Regarding, alarm manager vs count down timer. Please see below.

Note: The Alarm Manager is intended for cases where you want to have your application code run at a specific time, even if your application is not currently running. For normal timing operations (ticks, timeouts, etc) it is easier and much more efficient to use Handler.

This took from official Android Docs.

In short, CountDownTimer is used for normal timing operation (during your app is running). While Alarm Manager allows you to schedule some operation even when your app is not running.

Hope this helps.