Battery Health Test

How to Use This Test

1. Open this page on a laptop, tablet, or phone to automatically detect your device's battery status.
2. View the battery level percentage, charging state, and estimated time to full charge or discharge.
3. Monitor the readings over time to observe discharge rate and battery behavior under different workloads.

What This Test Checks

This battery test uses the Browser Battery Status API to give you real-time information about your device's power status, helping you understand your battery's current condition.

• Current battery charge level as a percentage
• Charging or discharging status
• Battery state classification (Critical, Low, Optimal, High, Fully Charged)
• Live discharge or charge rate in % per hour, sampled in real time
• Charging speed assessment (Fast, Normal, Slow, Trickle) when plugged in
• Both the browser-reported and independently measured runtime estimates
• Session tracking: how much battery has been consumed since you opened the page
• Visual indicator of the 20–80% optimal long-term charging zone
• Context-aware recommendations based on your current battery state

Troubleshooting

If you're having issues:

• Try using Chrome, Edge, or Opera as these browsers have the best Battery Status API support.
• Firefox and Safari have limited or no support for the Battery API due to privacy restrictions.
• If you are on a desktop computer without a battery, the test will not be able to display any data.
• Ensure your browser is up to date for the best compatibility with the Battery Status API.

How to Check Real Battery Health on Your Device

The online test above reports your current charge level and charging state, but browsers do not expose battery health (wear and capacity loss) for privacy reasons. To see how degraded your battery is, use the built-in tool for your operating system:

Windows 10 / Windows 11

1. Open Command Prompt or PowerShell as Administrator.
2. Run powercfg /batteryreport /output "%USERPROFILE%\battery-report.html"
3. Open the generated HTML file from your user folder.
4. Compare Design Capacity vs Full Charge Capacity. A healthy battery is within 80-100% of design capacity; below 80% indicates noticeable wear.

macOS

1. Click the Apple menu and open System Settings (or System Preferences on older versions).
2. Go to Battery → Battery Health.
3. Read the Maximum Capacity percentage. Apple considers a battery healthy until it drops below 80%.
4. For more detail (cycle count, manufacture date), install the free coconutBattery app.

iPhone / iPad (iOS 16+)

1. Open the Settings app.
2. Tap Battery, then Battery Health & Charging.
3. Check the Maximum Capacity percentage. At 80% or below, iOS will suggest a battery replacement.

Android

Android does not expose battery health as consistently as iOS or macOS. Options by manufacturer:

• Samsung: open the Samsung Members app → Diagnostics → Battery status.
• Google Pixel (Android 14+): Settings → Battery → Battery health.
• All Android devices: dial *#*#4636#*#* in the Phone app to open the hidden Testing menu, then tap Battery information (availability varies).
• Third-party: AccuBattery learns your battery's capacity over a few charge cycles and reports estimated health.

Linux

1. Run upower -i $(upower -e | grep BAT) in a terminal.
2. Compare energy-full (current capacity) with energy-full-design (original capacity) to calculate wear.

Check Before Your Warranty or AppleCare Expires

If your battery is wearing out, a replacement may be free while the device is still covered. Apple replaces a battery at no charge once Maximum Capacity drops below 80% if you are under warranty or AppleCare+, and major Windows laptop makers (Dell, HP, Lenovo) apply a similar threshold. It is worth checking before coverage lapses:

1. Check your battery health using the steps above for your operating system.
2. If it is below 80%, look up your coverage by serial number (Apple: Check Coverage; Dell: Service Tag; HP/Lenovo: warranty lookup).
3. If you are still covered, book a battery replacement before the warranty expires.

Buying or Selling a Used Device?

Battery health is the first thing to check on a second-hand phone or laptop. As a rule of thumb, 90%+ is like-new, 85–89% is fine but worth a small discount, 80–84% means a replacement is due soon, and below 80% is flagged as worn. Always verify the figure on the device itself (Settings → Battery on iPhone; hold Option and click the battery menu on a Mac) rather than trusting a listing screenshot, since those can be faked. Inspecting a whole laptop? Run the used-laptop checklist to test the screen, keyboard and ports too.

What's Draining Your Battery

Capacity wear is gradual, but sudden fast drain usually has a specific cause. Check these first before assuming the battery is failing:

• Screen brightness: the display is the #1 power draw. Dropping brightness from 100% to 50% can add hours. Run the brightness test to calibrate a comfortable low level.
• Background GPU usage: on laptops, a browser or app pinned to the dedicated GPU drains 2-3x more than on the integrated GPU. Check with the GPU test to see which is in use.
• High refresh rate: 120 Hz or 144 Hz mobile displays use ~20% more battery than 60 Hz. Confirm your device's current rate with the refresh rate test.
• Poor cell signal: phones burn battery hunting for signal. Enable airplane mode in dead zones.

Frequently Asked Questions