Cognitive tools (e.g., calculators) provide all users with the same potential. Yet when people use such cognitive tools, interindividual variations are observed. Previous findings have indicated that 2 main factors could explain these variations: intrinsic cognitive skills (i.e., the “non–tool use” cognitive skills associated with the task targeted) and metacognitive beliefs about one's performance with tool use. In this study we sought to reproduce these findings and to investigate in more detail the nature of the relationships (i.e., linear vs. exponential) between tool use performance and intrinsic cognitive skills. In Experiment 1, 200 participants completed 2 cognitive tasks (calculation and geography) in 2 conditions (non–tool use vs. tool use). In Experiment 2, 70 participants performed a geography task in 2 conditions (non–tool use vs. tool use) and estimated their performance in each condition before completing the task. Results indicated that intrinsic cognitive skills and, to a lesser extent, metacognitive beliefs improved tool use performance: The higher the intrinsic cognitive skills and the higher participants estimated their tool use performance, the higher this tool use performance was. The nature of the relationship between tool use performance and intrinsic cognitive skills appeared to be linear rather than exponential. These findings extend previous research showing a strong impact of intrinsic cognitive skills on the performance associated with the use of cognitive tools or external aids.