battery

Battery status & health

Check your live battery status and estimate battery health from a Windows report or manual entry. All processing stays in your browser.

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Battery Health Checker

The browser cannot read true battery health from web pages. Use a Windows battery report, enter capacity values by hand, or use your phone's built-in setting. Every calculation runs locally.

If your device reports it.

Enter both capacities to see estimated health.

Battery reports are processed locally in your browser. Nothing is uploaded.

What battery health means

Battery health is a rough estimate of how much charge your battery can still hold, compared with when it was new. It is different from the battery percentage you see in the taskbar: percentage is how full today's smaller reservoir is, health is how big the reservoir has become over time.

Percentage versus health

A battery at 100% charge can still be worn. If the battery's full charge capacity has dropped to 70% of its design capacity, a full 100% charge holds only 70% as much energy as it did when the device was new. Live status shows the fill level; health shows the reservoir size.

Design capacity, full charge capacity, cycle count

Design capacity is the maximum energy the battery was engineered to hold when new (usually in mWh or mAh). Full charge capacity is the maximum energy it holds right now, at 100% charge. Cycle count is how many full equivalent discharges the battery has been through; two partial discharges of 50% count as one cycle.

Why browser-based battery data is limited

The web Battery Status API only exposes the current charge level and charging state. It does not expose capacity, cycle count, or health, and it was removed from Firefox and Safari for privacy reasons. True health values come from the operating system (powercfg on Windows, System Information on macOS, Settings on iPhone, or vendor tools on Android).

AIBattery advisor

Frequently asked

Can a website check battery health?
No. Web pages cannot read true battery health, capacity, or cycle count. The web Battery Status API only exposes the current charge level and charging state. Health estimates on this page come from a locally-parsed Windows battery report, from a value you enter, or from the built-in setting on your phone or laptop.
How do I check battery health on Windows?
Open Command Prompt or PowerShell as administrator and run "powercfg /batteryreport". Windows saves an HTML report to your user folder and prints the exact path. Drop that file onto the Windows Report tab and the health, wear, and cycle count are calculated in your browser.
What is a good battery health percentage?
90 to 100 percent is excellent, 80 to 89 percent is good, 70 to 79 percent is fair, 60 to 69 percent is worn, below 60 percent is heavily worn. These are practical guidance, not a hardware diagnosis. Real capacity varies with temperature and usage.
Can I check iPhone battery health online?
A normal website cannot read iPhone battery health. Apple exposes the value in Settings > Battery > Battery Health & Charging > Maximum Capacity. Enter that percentage on the Phone tab and the checker converts it to health and wear.
What is full charge capacity?
Full charge capacity is the maximum energy your battery can hold today, at 100 percent charge. It is compared against the design capacity, which is what the battery was engineered to hold when new. Health equals full charge capacity divided by design capacity times 100.
What does battery cycle count mean?
A cycle is one full equivalent discharge of your battery. Two partial discharges of 50 percent count as one cycle. Cycle count is a rough indicator of how much the battery has been used; a battery near the end of its rated cycle life is more likely to show reduced capacity.
Is my data private?
Yes. The Battery Status API reads the charge level in your browser. Windows battery reports are parsed locally with FileReader and DOMParser and never uploaded. Nothing you type into the manual calculator is sent to a server. Analytics only records the section and a bucketed health label.
Why does it say unsupported on my browser?
The Battery Status API is available in Chrome, Edge, and Opera. Firefox and Safari removed it for privacy reasons. The unsupported state is normal on those browsers; the Battery Health Checker below still works.