Your MacBook battery won’t last forever, no matter how well you look after it. If you’re plugging in more often than you used to, or your battery percentage seems to have a mind of its own, these are the signs your MacBook battery needs replacing.
Discover how to check your battery’s health in under a minute, what to watch for day-to-day, and when it’s time to swap it out.
How to Do a MacBook Battery Health Check
Before you spend a cent, run a quick MacBook battery health check. It takes less than a minute and tells you exactly where your battery stands.
Go to System Settings > Battery > Battery Health. You'll see one of three readings: Normal, Service Recommended, or Replace Now.
For more detail, hold Option and click the Apple menu, then choose System Information. Under Power, you'll find your Cycle Count and Maximum Capacity, the two numbers that show how much life is left in your battery.
1. The "Service Battery" Warning
If macOS flags "Service Recommended" or "Replace Now" under Battery Health, take it seriously. Apple's software is tracking your battery's actual capacity against what it shipped with, so this warning doesn't appear without reason.
2. MacBook Battery Draining Fast
A MacBook battery draining fast is usually the first thing people notice. If a full charge used to get you through a workday and now barely covers a couple of hours of light browsing, your battery's capacity has dropped well below its rated capacity.
3. High Cycle Count, Low Battery Health %
Every battery is rated for a set number of charge cycles, generally around 1,000 for most modern MacBooks. Check your MacBook battery cycle count in System Information. If you're close to or past that number, and Maximum Capacity has slipped under 80%, your battery is on its way out.
4. Random Shutdowns or Jumpy Percentage Readings
Does your MacBook turn off at 30% without warning? Or does the percentage drop suddenly, then jump back up once you plug in? Both point to a battery that can no longer deliver steady power under load.
5. Overheating During Light Use
An ageing battery can push your MacBook to run hotter than usual, even during simple tasks like browsing or checking emails. If the fan kicks in constantly for no obvious reason, the battery is often the cause.
6. A Swollen Case or Sticky Trackpad
This one's visual. A swollen battery can push against the trackpad or keyboard, or leave the bottom case slightly raised off the desk. Stop using your MacBook straight away if you notice this and get it looked at.
A swollen battery is a key indicator of when to replace your MacBook battery, since it's a safety issue, not just a performance one.
7. Your MacBook Is Over 3-5 Years Old
Even a battery with no obvious problems will degrade with age. If your MacBook is past the 3- to 5-year mark and you're noticing any of the signs above, age is likely playing a part.
Get the Right Parts for the Job
Don't wait for a full shutdown to make the decision for you.
Swapping a MacBook battery yourself is more achievable than most people think, with the right tools and a tested replacement battery. Most models just need a spudger, precision screwdrivers, and about 30 minutes. Not sure where to start? Our DIY videos walk you through it step by step.
Shop replacement MacBook batteries and repair kits from iGadget, backed by real warranties and shipped New Zealand-wide, and get your MacBook back to a full day's charge.
Frequently Asked Questions
When should I replace my MacBook battery?
As a rule of thumb, replace it once you notice two or more of the above signs your MacBook battery needs replacing, such as fast draining, random shutdowns, overheating, or if Maximum Capacity has dropped under 80% with a cycle count near its limit.
One warning on its own isn't a reason to panic. But stacked together, they mean your battery is no longer doing its job properly, and every day you wait is a day of reduced performance and a higher risk of a swollen cell.
Is it safe to keep using a MacBook with a failing battery?
For a while, yes, but a swollen battery is a genuine safety risk. If you spot any swelling, stop using your MacBook and replace the battery straight away.
Will a new battery fix slow performance?
Only if the slowdown is linked to thermal throttling from a struggling battery; if it isn't related to power delivery, it's worth checking your storage or RAM too.
