Lately, does your smartphone run out of battery quickly when playing games…? If it no longer lasts a full day, it may be a sign that your battery’s lifespan is coming to an end.

On this page, you can run a simple battery check to quickly diagnose its condition. Use it as a reference to know when it might be time for a replacement!

Discharge Tester v1.6 (EN)

Simple Smartphone Battery Checker

For more stable results, measure for at least 6 minutes (up to 15 minutes). Stop the test if the device feels hot.

Battery Test Result
Please start the test. The result will be shown here.
Current battery level
--%
Auto-detected on supported devices
Average rate (aggregate)
-- %/min
Approximate drop per minute
Elapsed time
00:00
0/5 cycles
Cycle progress: 0%
Controls
Android/Chromium devices auto-read the battery %. On iOS and other unsupported browsers, please enter the % at the start and at each cycle end.

How to Use This Tool

What This Tool Can Do

  • Discharge Test: Estimate battery health based on the speed of power decrease while unplugged (works even on the go)

How to Run the Battery Check (Discharge Test)

  • Unplug the charging cable and press Start Test.
  • Each cycle lasts 3 minutes. Up to 5 cycles (15 minutes) will run automatically, and the average result will be used for judgment.
  • On devices where auto % detection is not supported (mainly iOS), enter the current % manually at the start and end.
  • After completion, the result will be shown under Battery Test Result.

How to Read the Results (Discharge Rate)

Good: ≤ 0.35% / min Moderate: 0.35–0.60% / min Consider Replacement: > 0.60% / min

Charging tests will also be displayed with the same 3-level evaluation (reflected in “Battery Test Result”).

Tips for Better Accuracy

  • Perform the test at 40–80% battery, keep usage minimal, and in a cool environment.
  • Keep screen brightness consistent (not excessively high).
  • Auto detection on Android/Chrome works only on HTTPS pages.

※ Due to iOS restrictions, automatic battery % detection is not supported (manual input only).

Disclaimer

  • This tool is a browser-based simple battery check. It does not provide official diagnostics or warranty.
  • Results are for reference only, and may vary greatly depending on device conditions, temperature, battery level, background activity, charger/cable, network environment, and OS/browser specifications (e.g., Battery API unsupported).
  • If you notice heat, swelling, or unusual smells, stop immediately and consult a professional.
  • Features like Wake Lock (preventing screen sleep) may increase power consumption. Use at your own risk.
  • The provider assumes no responsibility for any damage, loss, or data deletion caused by use of this tool.
  • Privacy: If results are saved, they are stored locally in your browser (localStorage) and not sent to external servers (unless separately implemented).
  • Recommended environment: Automatic detection on Android/Chrome only works over HTTPS. iOS/Safari requires manual input.
  • This disclaimer may change without notice. By using the tool, you agree to the terms above.

※ For safety, stay near your device during testing. Stop immediately if overheating occurs.

Other Tools

When playing games on your smartphone, you can also use our FPS check tool to see your device’s frame rate.