Open Command Prompt as administrator
Type `powercfg /batteryreport` and press Enter
Open the generated battery report file from the shown path
Compare Design Capacity with Full Charge Capacity
Check Battery Cycle Count if available
Look at recent battery usage and capacity trends in the report
On Windows, open Settings > System > Power & battery to review battery usage
On macOS, hold Option and click the battery icon to view battery condition
On macOS, go to System Settings > Battery > Battery Health
Use the laptop manufacturer’s battery diagnostics tool
Check BIOS or UEFI battery diagnostics if available
Observe how quickly the battery drains during normal use
Note any sudden shutdowns, swelling, overheating, or charging issues