Balance is similar to symmetry, but can be looser. A work has balance when the elements are roughly even throughout a work. This can be accomplished through symmetry, but a work can also have asymmetrical balance.
Doryphoros (The Spearbearer), by Polykleitos, ca. 450–440 BCE has clear asymmetrical balance.
The figure does not stand in a symmetrical way, but overall, seems even, calm, balanced. In this case, the figure has his weight on his right leg, so this leg is tensed. The left leg is relaxed and bent. Balancing this out, the right arm hangs loosely, but the left arm is tensed. In this way, the body is balanced. For more on Doryphoros, see Proportion and Scale, and Naturalism.