We report results of two studies on metacognitive accuracy with undergraduate education students. Participating students were asked to judge their personal performance in a multiple-choice exam as well as to state their confidence in their performance judgement (second-order judgement [SOJ]). In each study, we compared four conditions that differed in the type of the presented 5-point confidence scale for SOJs. In Study 1, four bipolar scales with different labels were applied; in Study 2, unipolar and bipolar scales were implemented. The results of Study 1 with N?=?420 students show that undergraduates on average provided accurate performance estimations. However, students were not aware of their judgement accuracy, shown by a low fit of SOJ and judgement accuracy. In addition, the type of provided scale significantly influenced the SOJs. Study 2 with N?=?348 students replicated the findings of the first study and gave further insight into the effects of uni- vs. bipolar response scales.