Example: Battery capacity: 10,000 mAh · Device draw: 450 mA · Efficiency: 85% → Battery life: 18.9 hours.
In days (24/7 use): 0.8
Frequently asked questions
How do I calculate battery life? Enter your numbers above and the result updates instantly. For example: Battery capacity: 10,000 mAh · Device draw: 450 mA · Efficiency: 85% → Battery life: 18.9 hours.
Is this Battery Life Calculator free? Yes — completely free with no sign-up or paywall. It runs entirely in your browser and keeps working offline; the numbers you enter never leave your device.
How accurate is it? It uses the standard published formula for battery life. Results are estimates for planning — not financial, tax, medical, engineering, or legal advice.