All rechargeable batteries degrade over time. If you’ve ever wondered how your laptop’s battery is holding up this simple command will tell you how you can get some information. Run the following command: $ upower -d And look for the following line: capacity: 73.7304% As you can see my laptop’s battery holds 26% less power than it did when it rolled off the assembly line. When the charger is back in you can also find the time until it’s fully charged again.