How to Check Your iPhone Battery Health — and What the Numbers Mean

Where to find Battery Health on your iPhone

Apple puts the battery report in the Settings app, but the exact label depends on your model.

1. Open Settings.
2. Tap Battery.
3. Tap Battery Health on iPhone 15 and later models, or Battery Health & Charging on iPhone 14 and earlier.

You'll see two main readings: Maximum Capacity and Peak Performance Capability. Depending on your model and iOS version, you may also see a simple status line, such as Normal or Service, above them.

If you have an iPhone 15 or newer, there's one more useful number. Go to Settings › General › About and scroll to the battery section to see the Cycle Count, along with the battery's manufacture date and first use date.

Maximum Capacity: what the percentage means

Maximum Capacity compares how much charge your battery can hold today with how much it held when it was new. A brand-new iPhone shows 100%. As the battery ages, chemical wear inside the cells slowly reduces that number.

A reading of 90% means a full charge now holds about nine-tenths of what it did on day one. You'd notice that as needing to top up a bit earlier in the day, not as a dramatic change.

Apple says its batteries are designed to keep a Maximum Capacity of 80% after a set number of complete charge cycles: 500 for iPhone 14 and earlier, and 1,000 for iPhone 15 and later. A complete cycle is using 100% worth of charge in total, which can be spread across several partial charges.

These bands are a rule of thumb, not hard cut-offs. Two phones with the same reading can behave differently depending on how they're used.

Peak Performance Capability: the message that matters most

This section tells you whether the battery can still deliver bursts of power when the phone needs them, such as opening the camera or launching a game. It shows a sentence rather than a number. Here's how to read the common ones:

"Supporting normal peak performance"

All good. The battery can handle what the phone asks of it, even if Maximum Capacity has dropped a little.

An unexpected shutdown and performance management

If the phone has shut down because the battery couldn't deliver enough power, iOS may turn on performance management. This deliberately limits peak speed so the phone doesn't keep switching off. You'll see a note about it here, and an option to disable it. Disabling it can bring back speed but also the risk of shutdowns, so it's a stopgap, not a fix.

A message saying battery health is significantly degraded

This is the clearest sign the battery needs replacing. The phone will still work, but capacity and peak power are both noticeably reduced.

Battery health can't be determined, or no reading appears

This can show up when the battery was previously replaced with a part the iPhone doesn't recognize, or when the battery reporting has a fault. It doesn't always mean the battery is bad. A technician can test the battery directly and tell you what's going on.

Cycle count: a useful second opinion

On iPhone 15 and later, the Cycle Count helps you judge whether a reading makes sense. A phone with a low cycle count and a low Maximum Capacity may have spent time in heat, which speeds up wear. A high cycle count with a still-healthy reading means the battery has aged well.

If you're buying a used iPhone, these numbers are one of the quickest ways to judge how hard it has been used.

When replacing the battery makes sense

Use this checklist. If two or more apply, a battery replacement is likely worth it:

• Maximum Capacity is below 80%.
• Peak Performance Capability mentions performance management or degraded health.
• The phone shuts down before it reaches 0%, or in mild cold.
• You're charging more than once a day with normal use.
• The phone feels slow even after updates and restarts.
• You plan to keep the phone for at least another year, or pass it on to someone.

If the back looks raised, the screen is lifting or the phone gets unusually hot while charging, stop charging it and get it looked at. Don't press on it or try to open it yourself.

For a wider look at battery care, charging habits and Android battery checks, see our phone battery guide.

Need a hand?

If your numbers point to a worn battery, Woman Wireless On The Go can replace it where you are: at home, at work, in your parked car or in your condo lobby, across our service area. Send your iPhone model and a screenshot of your Battery Health screen and you'll get a free quote before any work starts. Your technician confirms timing when she quotes, then tests the phone with you once the new battery is in. Call or WhatsApp (365) 351-4247 or book online.

Frequently asked questions

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