Is it bad to leave a laptop plugged in all the time?

Why plugged in is not dangerous

Laptop charging is managed by a controller that cuts charging when the battery is full. The adapter then powers the machine directly. There is no overcharging in the sense of the old advice about unplugging at 100 percent.

What does wear a lithium-ion battery is time spent at a high state of charge, especially when it is hot. Apple states that a battery's lifespan depends on its chemical age, which is affected by factors such as temperature history and charging pattern. A laptop that sits at 100 percent on a warm desk for years is in the worst combination of the two.

What the makers say

Apple describes two features for Mac laptops in its Optimized Battery Charging and Charge Limit page. Optimized Battery Charging learns your routine and can delay charging past 80 percent when it expects the Mac to stay connected for a long time. Charge Limit, which needs macOS Tahoe 26.4 or later and a Mac with Apple silicon, lets you choose a limit between 80 and 100 percent. Apple also notes that the Mac will occasionally charge to 100 percent to keep its battery estimates accurate.

Apple's battery tips page adds that you should avoid ambient temperatures above 95 degrees Fahrenheit (35 degrees Celsius), and that storing a battery fully charged for an extended period can cause some capacity loss.

How to set a limit

The setting has different names by maker and the menu moves between versions. Look for "battery care", "conservation mode", "charge limit", "battery protection" or "adaptive charging".

Platform	Where to look
macOS Ventura 13 or later	Apple menu, System Settings, Battery, then the info button next to Charging. Turn Optimized Battery Charging on. On macOS Tahoe 26.4 or later on Apple silicon, pick a Charge Limit from 80 to 100 percent
Lenovo	The Lenovo Vantage app, under battery or power settings, usually has a conservation or charge threshold option
Dell	The Dell Power Manager app, or the BIOS under power management, offers battery charge settings
HP	The BIOS under power management, or the HP support app, may offer a battery care option
ASUS and others	The maker's own app, often called MyASUS or similar, under battery health

Not every model has the feature, and older machines often do not. If your laptop has no setting, nothing is broken. The machine is simply handling charging in its own way.

Practical habits that help

1. If the laptop is mostly stationary, enable a limit near 80 percent where available. You lose some runtime on the rare day you travel, but the battery will age more slowly.
2. Before a trip, charge it fully, or use the "charge to full now" option if your system has one.
3. Keep vents clear. Heat matters more than the plug. Setting the laptop on a soft surface raises temperature, and the thread on a loud fan covers the airflow side.
4. Do not leave a swollen or hot battery plugged in. If the case bulges or the laptop gets unusually hot at the battery, unplug it and get it serviced.
5. If you store the laptop for months, leave it around 50 percent charged, as Apple advises, rather than full or empty.

What about removing the battery

On the few laptops with a removable battery, some people take it out and run on the adapter. That can work if the adapter is a good one, but you lose the protection of a battery during a power cut or a cable bump. On most current laptops the battery is internal and this is not an option.

The thread on battery lifespan covers how to tell when the battery has worn out regardless of how it was charged.