Most people would never guess that there is a tool to measure battery usage in Windows. I first discovered this when trying to figure out what was draining my battery on my Surface Pro 3. For a quick overview of battery drain by app, you can use the Windows Battery Saving settings.
Windows Battery Saver
To access this, type in Windows Battery Saver in the Start Menu search.
To get battery usage by app, select the option to option to _view battery usage by app. _This will give you a quick overview of what apps are draining your battery. It should come as no surprise that Google Chrome is almost always at the top of the list.
Powercrfg
If you want a more extensive report, than you can use powercfg. Open up command prompt and type in the following:
powercfg /BATTERYREPORT
This will generate an html file filled with very in-depth information such as your estimated capacity, your battery drain over time and battery life estimates.