Battery Backup Runtime Calculator
Calculate how long a battery backup system will power your devices during an outage
About this calculator
The Battery Backup Runtime Calculator determines how long your UPS or backup battery system will keep your devices running during a power outage. By inputting your battery capacity, device power consumption, and system efficiency, you get an accurate estimate of backup duration. This tool is essential for planning emergency power needs, ensuring critical equipment stays operational, and selecting appropriately sized backup systems for homes, offices, or data centers during unexpected power failures.
How to use
Enter your battery's capacity in amp-hours (Ah) or watt-hours (Wh), input the total power consumption of connected devices in watts, and specify your system's efficiency percentage. The calculator will instantly display the estimated runtime, helping you understand how long your backup power will last during an outage.
Frequently asked questions
How do I find my battery's capacity?
Check the battery label for Ah (amp-hours) or Wh (watt-hours) ratings, or consult your UPS manual for specifications.
What affects actual runtime compared to calculated estimates?
Battery age, temperature, discharge rate, and actual device power consumption can reduce runtime below calculated estimates.
Should I include all connected devices in power calculations?
Yes, include all devices that will draw power during an outage, including any standby power consumption.