This paper gives expressions to calculate the fraction of power, fPIB, from a given multimode
gaussian laser beam that can be deposited within a bucket of radius, rT, on a target at a range,
zT, using a focusing optic of diameter, Df. We relate the power in the bucket, fPIB, to the M2
parameter, both of which can be experimentally measured. In this paper, we have also
presented relationships between these two parameters and BQ and Strehl, which have not been
unambiguously defined for a multimode laser beam in the literature. We propose fPIB and M2
to be used as standard design parameters instead of BQ and Strehl for laser-target interaction
tests with multimode laser beams from stable resonators.