Safe drug calculation is important in nursing as insufficient skills pose a risk to patient safety. Therefor solid education in mathematics for undergraduate nursing students must be provided. To support nursing students' skills in drug calculation, a web-based learning platform for drug calculation was created. The aim of this study was to investigate nursing students' experiences of a web-based learning platform for drug calculation in terms of usability and learning support. The study was a cross-sectional comparative study. Ninety-five nursing students participated, out of which 46 students were in semester one and 49 students were in semester six. A questionnaire was used to evaluate the nursing students' experiences of a web-based learning platform for drug calculation in terms of usability and learning support. The findings were informed by statistical and thematic analyses. The majority of the participants evaluated the platform positively. The platform was deemed useful, and it was a support for the nursing students' learning. These findings provide that a web-based learning platform for drug calculation can be used as a complement to traditional lectures. Nevertheless, further research is required focusing teaching strategies facilitating different learning styles and level of computer skills.