The shift toward digital learning has become an essential direction in higher education, necessitating the development of relevant and effective instructional materials. This study focuses on the development of online-based Calculus learning materials assisted by GeoGebra, designed to support effective and engaging mathematics instruction in digital environments. The research employed a Research and Development (R&D) approach, evaluating both the practicality and effectiveness of the materials. Data were collected through questionnaires and basic Calculus tests administered to 20 students from the Mathematics Education Study Program at Universitas Islam Negeri Syekh Ali Hasan Ahmad Addary Padangsidimpuan, North Sumatra, Indonesia, who had completed the Basic Calculus course. Practicality was assessed based on user responses, while effectiveness was measured through student performance. The results indicated that the developed materials fall into the “good” category, with a practicality score of 3.36 and an effectiveness score of 72.75. These findings suggest that the GeoGebra-assisted, online-based Calculus materials are suitable for implementation as an alternative resource in digital Calculus instruction. However, further refinement is recommended—particularly in enriching content that fosters learner creativity and integrates realistic mathematics education approaches. Enhancing these aspects could strengthen the material’s capacity to support deeper conceptual understanding and active engagement in online learning settings.