How to Tell If Your Phone's Battery Is Failing

Your phone rarely announces a failing battery outright — it shows up in small, everyday annoyances first. Here's what to watch for.

1. Your phone dies faster than it used to

Every battery loses some capacity over time — that's normal. But if a full charge that used to last you a whole day now barely gets you through the morning, that's a sign worth paying attention to.

2. Sudden shutdowns at higher charge levels

If your phone powers off unexpectedly while still showing 20%, 30%, or even 50% battery, it's often a sign the battery can no longer deliver power reliably under load — even though it still reads a charge on the screen.

3. Slow or inconsistent charging

A battery nearing the end of its healthy life often takes noticeably longer to charge, or charges in fits and starts rather than smoothly climbing to 100%.

4. The phone feels warm even when idle

Some warmth during heavy use or charging is normal. But a phone that runs warm while just sitting in your pocket, doing nothing, can point to a battery working harder than it should to hold a charge.

5. Visible swelling

If the back cover or screen looks slightly lifted, bulged, or hard to close — stop charging the phone immediately and have it looked at. A swollen battery is a safety issue, not just a performance one.

What to do next

Any one of these signs on its own isn't necessarily a diagnosis — plenty of phones run warm or shut down for unrelated reasons. The only way to know for sure is to actually measure the battery's health rather than guess from symptoms.