Battery Life Calculator
Calculate how long your battery will last based on capacity and device consumption
Calculate Battery Life
Usually printed on the battery or in device specifications
Average current consumption of your device
Percentage of battery capacity never used to prevent damage
Sleep Mode Analysis
Input Error
Battery capacity must be greater than 0
Common Device Examples
Smartphone
Capacity: 4500 mAh
Current: 1000 mA
Safety: 20%
Tablet
Capacity: 8000 mAh
Current: 1500 mA
Safety: 20%
Laptop
Capacity: 4400 mAh
Current: 2000 mA
Safety: 10%
IoT Device
Capacity: 2000 mAh
Current: 50 mA
Safety: 20%
Flashlight
Capacity: 3000 mAh
Current: 500 mA
Safety: 10%
Remote Control
Capacity: 1000 mAh
Current: 10 mA
Safety: 20%
Discharge Safety Guide
Li-ion/LiPo
Safety: 20-30%
Never discharge below 3.0V per cell
NiMH
Safety: 10-20%
More tolerant to deep discharge
Lead Acid
Safety: 50%
Avoid deep discharge for longevity
Typical Current Draw
Battery Life Tips
Use sleep mode to extend battery life dramatically
Lower screen brightness to reduce power consumption
Disable unnecessary features like GPS, WiFi when not needed
Temperature affects battery performance significantly
Understanding Battery Life Calculation
Basic Formula
The battery life calculator uses the fundamental relationship between battery capacity and device consumption:
Sleep Mode Calculation
For devices with sleep modes, we calculate the average consumption based on the time spent in each state:
Key Factors
Battery Capacity
Measured in mAh or Ah, indicates how much charge the battery can store
Current Consumption
How much current your device draws, varies with usage and features
Discharge Safety
Prevents over-discharge damage, varies by battery chemistry
Sleep Mode
Dramatically reduces power consumption during inactive periods
Example Calculation
Smartphone Example:
- • Battery: 4500 mAh
- • Current draw: 1000 mA (average use)
- • Discharge safety: 20%
- • Sleep mode: Not considered
Calculation:
- • Effective capacity: 4500 × 0.8 = 3600 mAh
- • Battery life: 3600 ÷ 1000 = 3.6 hours
- • Result: 3 hours 36 minutes