Checked 
Turn on the percentage
Open Settings, go to Battery, then enable Battery Percentage. Your iPhone will show the remaining charge as a number, either inside the battery icon or next to it depending on your model and iOS version.
Why it helps
The battery icon is easy to misread. A phone at 38 percent and one at 24 percent can look close enough when you are in a hurry. The percentage gives you a clearer signal before a commute, meeting, hotspot session, or long call.
Good to know
The exact display can vary by iPhone model and iOS version. If you do not see the option, update iOS or search Settings for Battery Percentage.
When it is most useful
This small setting pays off when you are navigating, recording video, sharing a hotspot, or spending a day away from a charger. You make charging decisions from a real number, not a rough icon.
Sources
Selected references used to verify or support this tip.
- Show the battery percentage on iPhone Apple Support · official_docs