Battery Capacity gives more detailed feedback about battery health than the default OS battery states (normal, replace, service).
Battery Capacity is a realion between “Full Capacity” and “Design Capacity". Full capacity can be reached once you fully charge your Mac, this value decreases during usage. Design Capacity is the factory default of your battery so it will not lower.
In case if your battery capcaity is low, but you still see Normal for “Battery Condition”, there is no need to do anything. Once Battery Condition turns to Replace, you’ll need to think about replacing the battery. Read more about Mac notebook batteries.