Paul suddenly recalls having baptized the household of Stephanas
as well. It was common practice to baptize whole households together. Many of these households would also include children (as seems to have been the case with Lydia’s household, since Scripture says that she came to faith but that she and her household were baptized, Acts 16:15). A household (parents, children, and slaves) was viewed as a unity. This is also indicated by Paul’s words to the jailer: Believer in the Lord Jesus, and you will be saved, you and your household
(after which the jailer and his family were baptized, Acts 16:31–33).
16 (I did baptize also the household of Stephanas. Beyond that, I do not know whether I baptized anyone else.)