To assess the occurrence and frequency of bipolar at-risk symptoms in a large sample of previously undiagnosed students using the new screening tool Bochumer Screeningbogen Bipolar (BSB). 2329 students of the Ruhr-University Bochum, Germany completed online demographic data as well as various self-rating questionnaires (BSB; Hypomania Checklist 32; Altman Self-Rating Mania Scale; Beck Depression Inventory). Within the student cohort (64.4% female, mean age 24.3 years) every fifth student currently suffered from moderate to severe depressive symptoms; every sixth student had already thought about suicide and every other student reported a history of mood swings. The most frequently reported depressive symptoms included physical exhaustion, depressed mood, and tiredness. The most frequently reported (hypo)manic symptoms included physical agitation, feeling extremely energetic, and lack of concentration. The BSB showed good convergent validity with other established questionnaires capturing depressive or (hypo)manic symptoms, as well as a stable administration of underlying constructs. The BSB correlated significantly with the already established applied questionnaires. The predictive power of the BSB regarding the development of bipolar disorder cannot be correctly quantified at present. The further purpose of this exploratory web-based study should be to examine the validity of the presented measures in a longitudinal design.