Ever wondered why your laptop runs out of battery even though windows shows many more minutes? Its solely because windows doesn't consider the rate of discharge and the battery wear. Rate of discharge is the rate at which the battery is being used up ; which is measured in mW ,and battery wear is the part of your battery which is no longer used in the charging and discharging. Here is a utility which accurately calculates battery life and displays it in the task bar. Well this tiny utility does wonders , I recommend it as a must have for all portables running windows. Just download the free version as the pro one has a few little things which do not matter much. Head over to the download here.