Use our online calculator to estimate the battery life storage rating by entering the capacity rating of battery and consumption of the device. Battery life is computed based on current rating in Milli Ampere per Hour (mAh). Ampere is a unit of measurement of current flow towards the load. Calculate battery storage by inputting current rating of the battery and load current of the circuit. Less load current gives more battery life. This battery life calculator will help to measure the battery performance and longevity.