Phone Battery Test

Check your battery level, charging status, and estimated time remaining — instantly in your browser.

⚠ Battery API Not Supported

Your browser doesn't support the Battery Status API. This is common on:

To check battery on iPhone: Settings → Battery. On Android: Settings → Battery or the status bar.

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○ Detecting...
Level
Battery remaining
Charging
Est. Time

About This Battery Test

This tool uses the browser's Battery Status API to read your device's battery information in real time. The data updates automatically as your battery charges or discharges.

What Do the Numbers Mean?

Level is your current battery percentage. Charging shows whether your device is plugged in. Estimated Time is the browser's prediction for how long until fully charged or fully discharged — this is an estimate based on current consumption rate.

Why Is iPhone Not Supported?

Apple removed the Battery Status API from Safari in iOS 12 for privacy reasons — it was being used to fingerprint users. On iPhone, check your battery via Settings → Battery or the status bar percentage.

Frequently Asked Questions

How do I check battery health on Android?
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This page shows your current battery level and charging status. For deeper battery health (capacity vs. original), go to Settings → Battery → Battery Health (varies by Android version and manufacturer). Samsung devices have this under Settings → Device Care → Battery.
How do I check battery health on iPhone?
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On iPhone, go to Settings → Battery → Battery Health & Charging. A maximum capacity of 80% or above is considered healthy. Below 80%, Apple recommends battery replacement.
Does a low battery percentage mean the battery is bad?
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No. A low battery percentage just means you need to charge. Battery health is a separate measurement of how much capacity the battery has retained compared to when it was new. A fully charged old battery may only hold 75% of its original capacity.
Should I charge my phone to 100%?
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For lithium-ion batteries, keeping charge between 20–80% helps extend long-term battery health. Consistently charging to 100% or letting it drop to 0% accelerates degradation. Many modern phones have optimized charging modes to help with this.
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ABOUT THIS TOOL

Online Battery Test — Check Your Device Battery Status

This tool reads your device battery status using the browser Battery Status API — showing current charge level, charging state, and estimated time to full charge or discharge. It works on Android devices, laptops, and Windows/Mac computers where browsers expose battery information.

Why Does iOS Not Show Battery Info?

Apple removed battery API access from Safari on iOS in 2019 citing privacy concerns — battery level data can theoretically be used for device fingerprinting. This is a Safari/iOS policy, not a hardware limitation. Android and desktop browsers still support battery access.

What Is Battery Health?

Battery health measures how much charge capacity remains compared to when the battery was new. A battery at 80% health holds 80% of its original charge. Lithium-ion batteries typically lose 20% capacity after 300–500 full charge cycles.

How to Preserve Battery Life

Keep charge between 20–80% for long-term health. Avoid frequent full 0–100% cycles. Use original chargers. Avoid extreme heat. Enable optimized charging features if your device supports them.

When to Replace Your Battery?

Replace when health drops below 70–75% (noticeable shorter usage time), when the battery causes shutdown before reaching 0%, or when physical swelling occurs (replace immediately — this is a safety hazard).

Frequently Asked Questions

How do I check battery health on Windows?

Open Command Prompt as administrator and run: powercfg /batteryreport. This generates a full battery report including design capacity vs current capacity, showing exact battery health percentage.

How do I check battery health on Mac?

Hold Option and click the Apple menu → System Information → Power. Look for "Cycle Count" and "Condition." Or go to System Settings → Battery → Battery Health for a simpler view. Apple considers batteries with condition "Normal" healthy.

Why does estimated time remaining fluctuate?

Battery time estimates are based on current power draw, which changes constantly. Running a heavy task like video rendering dramatically shortens the estimate, while idle usage extends it. The estimate stabilizes after a few minutes of consistent usage.