This problem has several potential causes, each with a corresponding fix.
To learn how to fix issues with an iPhone battery draining fast, run with this in order.
Most are fast, easy ways to fix the problem and increase battery life.

Getty Images/Artur Debat
A faulty app may drain power from an iPhone.
Generally, quitting an app on an iPhone doesn’timprove battery life on an iPhone.
However, if something is wrong with the app, it might cause a problem.
Look for anything that uses a high amount of power and exit the app, if necessary.
Connect to Wi-Fi or turn off Wi-Fi.
Turn off Wi-Fi andprevent it from connecting automatically, orput the phone in Airplane Modeto reduce the drain.
It changes the color theme on the machine to darker colors that require less battery power.
Place the iPhone face down when receiving notifications.
Every time youreceive a notification on your iPhone, the phone’s screen lights up.
The more notifications you receive, the faster the battery drains.
However, if you leave the iPhone face down, this can help avoid battery drainage.
The iPhone will still receive notifications, but the screen won’t light up.
Turn off push mail on the iPhone.
Disable Raise to Wake.
Go toSettings>Display and Brightness, then toggle theRaise to Wakeswitch to off (gray).
Turning off Raise to Wake improves the iPhone’s overall battery life.
Configure widgets and notifications.
However, each of those widgets requires battery power to maintain a connection and keep data relevant.
Reducing the number of widgets helps stop the iPhone battery from draining too quickly.
Many users experienced the battery going from full charge to 20% within a couple of hours.