How many musicians are in a full symphony orchestra?

How to get close to this number

Count the sections. Strings are by far the largest at several dozen, woodwind and brass are a handful each in pairs or threes, percussion is a small group, and there are a few specialists. Adding sections rather than instruments gives you roughly a hundred, and it reconstructs the structure at the same time.

The balance in the explanation is the insight, and it is acoustic rather than artistic. A single trumpet can overwhelm a dozen violins, so the string section needs its numbers simply to be heard. The composition of an orchestra is a solution to a volume problem, which is why the proportions have stayed stable across two centuries of repertoire.

Orchestra size is not fixed, though. A Classical-era symphony calls for a much smaller ensemble than a late Romantic one, and orchestras expand or contract for the work being performed rather than maintaining a constant roster. The figure describes a full modern symphony orchestra, which is the largest standard configuration rather than a universal one.