This research was inspired by the phenomenon of binge-watching Korean television drama series (K-dramas) among Taiwanese university students. K-drama fever may provide an impetus for sustained English-subtitled K-dramas viewing, which may serve as an alternative to extensive reading of graded readers that English teachers often encourage their students to do. The researcher compiled a corpus of 25+ million English-subtitled words from 240 different K-dramas, totaling 5,398 episodes and measured the vocabulary levels thereof along the BNC/COCA word-frequency scale. Results show that K-drama English subtitles reached the 2000-3500 word-family levels at 95% text coverage and extended to the 4000-5500 levels at 98% coverage subject to genres. EFL K-drama fans can encounter most of the first 5000 word families often enough for potential learning to occur through their continually watching up to 48 English-subtitled K-dramas. The results may serve as a reference for extensive reading practitioners and learners who are concerned with a certain vocabulary goal within the first 5000 word families.