How to find the total capacity of a laptop battery
As your battery gets older, the total capacity it's capable of holding decreases. Unfortunately, knowing the difference between the battery's designed capacity and current total capacity is not possible with most operating systems.
To determine this detailed information, install a third-party utility capable of reading and displaying the battery information. For Microsoft Windows users, we suggest getting the free BatteryCare laptop battery tool.
Can I increase the total capacity?
No. Over time all rechargeable batteries will lose some of the capacity they're designed to hold. After several years, all rechargeable laptop batteries needs to be replaced.