In baseball statistics, on-base percentage (OBP; sometimes referred to as on-base average/OBA, as the statistic is rarely presented as a true percentage) is a statistic generally measuring how frequently a batter reaches base. Specifically, it records the ratio of the batter's times-on-base (TOB) (the sum of hits, walks, and times hit by pitch) to their number of plate appearances. It first became an official MLB statistic in 1984.

Can we conclude that does hit by pitch count towards on base percentage?
yes