Battery Life Calculator

Device
mAh
hrs
hrs
min
cycles

Battery Life Calculator: How Long Will Your Phone Last?

Stop guessing. Our battery life calculator predicts exact runtime, drain rate, and health based on screen time, gaming, and standby usage.

How It Works

Runtime = Effective Capacity / Avg Drain Rate
Avg Drain = (Screen × 600 mAh/hr) + (Standby × 15 mAh/hr) + (Gaming × 1200 mAh/hr)

Average Battery Capacities

DevicemAhRuntime (5h screen)
iPhone 153349~6.5 hrs
Samsung S244000~7.8 hrs
Laptop50000~8–10 hrs
Smartwatch300~24 hrs

Example: 4000 mAh Phone

Screen: 5 hrs → 3000 mAh
Standby: 19 hrs → 285 mAh
Gaming: 1 hr → 1200 mAh
Total: 4485 mAh → ~89% daily
Runtime: 7.8 hrs

Battery Health Guide

  • 0–300 cycles: 100%
  • 300–500: 90–95%
  • 500–800: 80–85%
  • 800+: Replace

Pro Tips

  • Lower brightness 50%
  • Turn off GPS when not needed
  • Use dark mode
  • Charge 20–80%

Common Myths

  • Overcharging kills battery — modern devices stop at 100%
  • Close all apps — not needed

FAQs

Fast charging bad? Slightly reduces lifespan.

Replace at 80%? Yes for heavy users.

Laptop unplugged? Keep 50% for longevity.

Conclusion

Extend your battery. Use our free calculator daily.

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