Windows has a built-in battery diagnostic tool that generates detailed HTML reports about battery health.

Generate Battery Report

Open Command Prompt or PowerShell and run:

Command 
powercfg /batteryreport

Success message appears:

Command 
Battery life report saved to C:\Windows\System32\battery-report.html

View the Report

Navigate to the file location and open battery-report.html in any browser.

Quick access:

Command 
powercfg /batteryreport /output "%USERPROFILE%\Desktop\battery-report.html"

This saves report to your Desktop for easier access.

What the Report Shows

Installed batteries: Battery name, manufacturer, serial number

Recent usage: Last 3 days of battery drain and charge cycles

Usage history: Battery usage over time

Battery capacity history: Design capacity vs current full charge capacity

Battery life estimates: Estimated battery life at full charge

Key metric - Design vs Full Charge Capacity:

  • Design capacity: Original battery capacity when new
  • Full charge capacity: Current maximum capacity

If full charge capacity is significantly lower than design capacity, battery is degrading.

Battery Health Calculation

Command 
Battery Health = (Full Charge Capacity / Design Capacity) × 100

Example:

  • Design capacity: 50,000 mWh
  • Full charge capacity: 42,000 mWh
  • Battery health: 84%

Below 80% indicates significant degradation. Below 50% means battery replacement recommended.

Energy Report (More Detailed)

For comprehensive system power analysis:

Command 
powercfg /energy

Analyzes system for 60 seconds, generates energy-report.html.

Shows:

  • Power efficiency issues
  • Battery drain causes
  • Device power consumption
  • CPU performance issues

Sleep Study Report

Diagnose why laptop drains battery during sleep:

Command 
powercfg /sleepstudy

Generates sleepstudy-report.html showing what prevented deep sleep.

Mac Battery Info

System info:

Command 
system_profiler SPPowerDataType

Shows battery cycle count and condition.

Menu bar: Hold Option key, click battery icon. Shows condition and cycle count.

Linux Battery Info

Command line:

Command 
upower -i /org/freedesktop/UPower/devices/battery_BAT0

Or:

Command 
cat /sys/class/power_supply/BAT0/capacity

Shows current battery percentage.

Common Battery Issues

Report shows rapid degradation: Battery worn out, consider replacement.

High cycle count: Over 500 cycles on most laptops indicates aging battery.

Low full charge capacity: Less than 80% of design capacity means noticeable battery life reduction.

Fast drain during sleep: Run /sleepstudy to identify wake sources.

Bottom Line

Generate battery report:

Command 
powercfg /batteryreport

Opens in browser. Check "Full charge capacity" vs "Design capacity" to assess battery health.

Save to Desktop for easier access:

Command 
powercfg /batteryreport /output "%USERPROFILE%\Desktop\battery-report.html"

Battery health below 80% indicates replacement may be needed soon.