Bases on balls per 9 innings pitched

$BB/9IP = 9 \cdot \frac{BB}{IP}$

In baseball statistics, bases on balls per 9 innings pitched (BB/9IP or BB/9) or walks per nine innings (denoted by W/9) is the average number of bases on balls, (or walks) given up by a pitcher per nine innings pitched. It is determined by multiplying the number of bases on balls allowed by nine and dividing by the number of innings pitched. It is a measure of the bases on balls ability of a pitcher.