  Supercuspidal representations are usually infinite-dimensional, so the size
of such a representation cannot be measured by its dimension; the formal degree
is a better alternative. Hiraga, Ichino, and Ikeda conjectured a formula for
the formal degree of a supercuspidal in terms of its $L$-parameter only. Our
first main result is to compute the formal degrees of the supercuspidal
representations constructed by Yu. Our second, using the first, is to verify
that Kaletha's regular supercuspidal $L$-packets satisfy the conjecture.
