Check Laptop Battery Health on Windows with the powercfg Battery Report

Open Windows Terminal or Command Prompt and run powercfg /batteryreport. Windows creates an HTML file in the current folder. Open it in a browser and compare Design capacity (what a new battery holds) with Full charge capacity (what yours holds now) under Installed batteries; dividing full charge by design gives your battery health as a percentage.

Who this is for

This is for anyone whose Windows laptop seems to run out of charge faster than it used to and who wants a measurement before paying for a replacement battery or a new laptop. You will end with a battery report, a calculated health percentage, an understanding of what the other report sections show, and a decision framework. It applies to Windows 10 and Windows 11 laptops and tablets that have a battery.

What powercfg is

powercfg.exe is a command-line tool built into Windows. Microsoft documents it as a way to control power plans, the sleep states and device power states, and to analyse the system for energy-efficiency and battery-life problems. One of its options, /batteryreport, generates a report of battery usage characteristics over the lifetime of the system.

Prerequisites

• A laptop or tablet with a battery that reports to Windows. Desktops have no battery. Microsoft's BatteryReport documentation says values return null when the battery is not present or when the value is not reported by the battery controller.
• Windows Terminal, Command Prompt or PowerShell.
• A web browser to open the HTML file.
• Ideally, the laptop charged to 100 percent before you read the numbers, with no heavy tasks running. A reading taken right after a long discharge can mislead, which is explained in the troubleshooting section.

Generate the battery report

Quick method

1. Right-click Start and select Terminal (or Windows Terminal). Command Prompt and PowerShell also work.
2. Run:

powercfg /batteryreport

3. The command prints the path of the saved file. Microsoft says it generates an HTML report file in the current path, so a terminal opened in your user folder saves it there.

If the command reports an error about writing the file, choose a folder you own with /output, shown next.

Choose where the file is saved

The /output option sets the path and file name:

New-Item -ItemType Directory -Path C:\Temp -Force | Out-Null
powercfg /batteryreport /output "C:\Temp\batteryreport.html"
Invoke-Item "C:\Temp\batteryreport.html"

Invoke-Item opens the file in your default browser. Create the folder first if it does not exist, as the first line does.

Limit the period or save XML

Microsoft documents two more options for this command:

powercfg /batteryreport /duration 14
powercfg /batteryreport /output "C:\Temp\batteryreport.xml" /xml

/duration sets the number of days to analyse. /xml formats the report as XML, which is easier to process with scripts. Use the HTML for reading.

Read the report

The report opens with general information about the computer, then moves to the battery. The key section describes the installed battery.

Design capacity and full charge capacity

Microsoft's Windows API documentation defines the two values you need:

Both are shown in milliwatt-hours (mWh) in the report. A new battery has a full charge capacity close to its design capacity. Over time, full charge capacity falls as the battery ages.

Calculate battery health

Use this simple formula:

Battery health (%) = Full charge capacity / Design capacity x 100

For example, with a design capacity of 50,000 mWh and a full charge capacity of 40,000 mWh, health is 80 percent. Those numbers are an illustration, not a measurement from a real machine.

You can calculate it in PowerShell too:

$design = 50000
$full   = 40000
[math]::Round($full / $design * 100, 1)

Replace the two values with the numbers from your report, without commas.

Other sections

The report also contains tables for how the laptop has used its battery. Typical sections include recent usage, battery usage over the last days, usage history, battery capacity history and battery life estimates. Look at the capacity history if you want to see wear over weeks or months rather than one reading, and the usage sections to see how long the battery actually lasted on recent days.

Some labels vary by Windows version and manufacturer. If you do not see a particular section, rely on the capacity numbers and your own experience of runtime.

Decide whether to replace the battery

There is no universal Microsoft threshold. Use the report together with these checks.

Check your laptop's warranty and the manufacturer's support page. Many makers define what counts as a battery defect, and the rules differ by brand and country. Use the report as supporting evidence when you speak to support.

Try software fixes first

Microsoft's guidance for saving battery life includes choosing a more efficient power mode, shortening the screen-off and sleep timers, using battery saver, and closing apps you are not using. In Windows 11 the power mode is under Settings, System, Power and battery, and Microsoft says you can choose a different option for Plugged in and On battery. The Energy recommendations panel on the same page can apply several power-saving settings at once. See /blog/laptop-fan-noise-loud-fix-cleaning for how power mode also affects heat and fan noise.

Replacement options

Replacing the battery is often cheaper than replacing the laptop. Use the manufacturer's service centre or an authorised repairer, and a battery that matches the model. Some thin laptops have the battery glued in, which makes DIY replacement difficult and risky; if the maker gives a service guide for your model, use it. Check the price from the maker's official page at the time you decide, as prices change.

Verify and track over time

1. Save the first report and note the date, design capacity, full charge capacity and your health percentage.
2. Run the command again every few months and compare the new full charge capacity with the old one.
3. A steady slow decline is normal. A sudden drop deserves attention.

Keep the HTML files in a folder named by date, for example batteryreport-2026-10-28.html, so you can compare them later.

Troubleshooting

Checklist

• Charge the laptop fully and close heavy apps.
• Run powercfg /batteryreport /output "C:\Temp\batteryreport.html" and open the file.
• Note design capacity and full charge capacity, and calculate the percentage.
• Compare with your real-world runtime and with older reports.
• Try power mode, brightness and background-app changes first.
• Contact the maker or an authorised service centre if capacity is low or the battery is swollen.
• Repeat every few months and keep the reports.

References

• Microsoft Learn, Powercfg command-line options: https://learn.microsoft.com/en-us/windows-hardware/design/device-experiences/powercfg-command-line-options
• Microsoft Learn, BatteryReport class (Windows.Devices.Power): https://learn.microsoft.com/en-us/uwp/api/windows.devices.power.batteryreport
• Microsoft Support, Change the power mode for your Windows PC: https://support.microsoft.com/en-us/windows/change-the-power-mode-for-your-windows-pc-c2aff038-22c9-f46d-5ca0-78696fdf2de8
• Microsoft Support, Battery saving tips for Windows: https://support.microsoft.com/en-us/windows/experience/power-battery/battery-saving-tips-for-windows