Between 2018-2021, eight European medical schools took part in a study to develop a medical knowledge Online Adaptive International Progress Test. Here we discuss participants' self-perception to evaluate the acceptability of adaptive vs non-adaptive testing. Study participants, students from across Europe at all stages of undergraduate medical education with varying levels of prior experience with progress testing, sat remotely invigilated tests using the online QuizOne® platform. Participants completed online feedback questionnaires on their experiences and perceptions of adaptive and non-adaptive tests. Overall satisfaction with the organisation and delivery of remote online tests was high regardless of previous experience with progress testing, differences in stages, programmes, and to some degree language. In statements probing the appropriateness of the level and the length of testing, differences were observed between adaptive and non-adaptive tests. There was a high level of agreement that the adaptive test was a good measure of personal knowledge and increased participants' motivation for study. Students' self-perception of the assessment is an important factor in evaluation of acceptability of the exam and its further development. In our study, the adaptive test algorithm adjusted the level of difficulty for the individual student in real-time, leading to positive perceptions of the length of the test and promoting students' engagement. The assessment increases student motivation for learning and in turn, has the potential to improve their performance.