B+ Trees are considered BALANCED because

1. the lengths of the paths from the root to all leaf nodes are all equal.
2. the lengths of the paths from the root to all leaf nodes differ from each other by at most 1.
3. the number of children of any two non-leaf sibling nodes differ by at most 1.
4. the number of records in any two leaf nodes differ by at most 1.

In B and B+ trees, all the leaf nodes will be at same level.