Despite the profound impact of Computational Chemistry (CC) on chemical research and understanding, it plays a negligible role in high school chemistry curricula. Integrating CC into high school education could enable students to engage in authentic science simulations and deepen their understanding of energy. To enable high school students to use CC, a freely accessible online learning environment, the Comp-Chem-Lab (www.comp-chem-lab.de/en), was developed based on qualitative empirical data from 80 German high school students in a design-based research approach. With this environment and the adaptive feedback implemented, most students were able to successfully use CC to determine the activation energy and released energy of a chemical reaction. A common progression of problem-solving strategies is for students to begin with trial and error but later to explore the relationship between chemical structure and energy more strategically based on their CC results. After searching for a “zero” energy structure, most students eventually activate the idea of energy minimization and successfully transfer it to another reaction step. Overall, the research highlights the potential of CC for enhancing high school and introductory college chemistry education but also emphasizes the need for further educational research to fully realize this potential.