With the increasing use of various web and online resources in the field of learning, it is important to propose and use reliable methods for evaluating the effectiveness of training courses. In this regard, this article analyzes various possible factors influencing the quality of learning, including pedagogical approaches, technical support and interface design. Some of them are recognized as key indicators that could be used to evaluate the overall course performance. For this purpose, a mathematical model based on these indicators is formulated for the purpose of evaluating the e-learning courses’ effectiveness. The performance indicators are separated into three groups related to the e-learning environment – visual indicators for course performance, technical indicators, and spent learning time. While the visual and technical indicators can be evaluated by the high-level management, the indicator about the time could be considered as feedback from the learners and expresses the average engagement of learners. The obtained results are based on the comparison of two web-based courses on programming at the University of Library Studies and Information Technologies in Bulgaria. It is shown that the combination of quality indicators and time factors can significantly improve the evaluation of the effectiveness of e-learning courses, providing a more accurate picture of knowledge acquisition and learner satisfaction.