What is the Battery Life Calculator?
Estimate how long a battery may support a steady average current load.
The model assumes the entered average load remains constant and that voltage is appropriate for the device.
Formula and calculation method
runtime hours = capacity mAh × efficiency × (1 − reserve) ÷ average load mA.
The calculation runs locally in your browser and uses only the values entered on this page.
Important limitations
Technology estimates simplify real systems. Hardware, software, network conditions, measurement conventions and manufacturer behavior can change actual results.
Planning scope: Use the result as an estimate and confirm critical sizing or configuration with current product documentation.
Battery Life Calculator FAQs
Temperature, battery age, load spikes, voltage conversion and cutoff behavior affect usable capacity.
Use a realistic average over the intended workload.
It is a simplified capacity model; discharge behavior differs by chemistry.
No. Results are educational estimates based only on the values and simplifying assumptions entered.
Yes. A displayed result is hidden as soon as an input changes so an old answer is not mistaken for a current calculation.
Yes. The form, colorful result panel and calculation steps are responsive for phones, tablets and desktops.
Sources and methodology
Official source links support terminology and measurement context. The arithmetic runs locally in your browser.