Full-time virtual schools problematize what it means to 'attend' school. Is it the length of time a child is logged on to the school's software system (regardless of the amount of work done), or the amount of work submitted (regardless of the log-on time)? How should one figure the amount of work teachers are doing when students work by themselves at home? Using data from documents and from interviews with 22 teachers from 10 full-time virtual schools in the U.S., this article examines schools as economies of institutional time, animated through two circuits of 'temporal accumulation': one producing students' individual academic records, a second tracking the quantity of time schools spend working with students. Cyber schooling reconfigures these circuits and their interlinkages, with implications for school funding, student certification, and teachers' work.