iPhone battery health: when to replace it

How to check your battery health

On an iPhone, go to Settings › Battery › Battery Health (on some models, Battery Health & Charging). It shows the battery's maximum capacity compared with when it was new.

When to replace it

Apple designs iPhone batteries to keep about 80% of their original capacity after a set number of charge cycles: 500 cycles for older models and 1,000 for the iPhone 15 and newer. Below 80%, most people notice the phone dying sooner, and iOS may slow the phone down to stop unexpected shutdowns.

Signs your battery is worn

• The phone switches off at 20 or 30%
• It won't last a full day any more
• It feels slow, especially in the cold
• Battery Health says "Service"

Swollen batteries: stop using the phone

If the screen is lifting, the back is bulging, or the phone rocks on a flat surface, the battery may be swelling. Stop charging it and get it replaced as soon as possible. Swollen batteries can damage the screen and are a fire risk.

Samsung and Android phones

Samsung phones show battery information in the Samsung Members app under Diagnostics, and recent models show it in Settings › Battery. The signs of a worn battery are the same. We replace batteries on Samsung, Google Pixel and other Android phones too.

Quick answers

Written by the technicians at Rugby Phone Repair Hub, who repair phones at customers' homes and workplaces across Rugby every day.

More help

• Phone won't charge? What to check first
• Dropped your phone in water? Do this now
• Cracked phone screen? What you need to know
• Green line on your Samsung screen?
• Phone won't turn on? Try this first
• How much does a phone screen repair cost?
• Phone screen flickering or showing lines?
• iPad won't turn on? Try this first
• Is it worth repairing my phone?
• iPhone "unknown part" message explained
• How to back up your phone before a repair