This study examined the effects of individual difference factors on the level of multiple text integration and the calibration accuracy among 190 seventh-grade students, including the mediating effects of perceived task and text difficulty. Collected data included reading self-efficacy, prior knowledge, multiple text integration product, perceived task and text difficulty, and self-evaluation scores. The PLS-SEM results indicated that reading self-efficacy lowered perceived task and text difficulty while enhancing the level of multiple text integration, and prior knowledge positively predicted the level of multiple text integration. Furthermore, higher perceived task difficulty was associated with greater calibration accuracy of the level of multiple text integration. Finally, the level of multiple text integration was a strong predictor of calibration accuracy. These findings confirm that a reader’s cognitive and affective resources serve as the driving force behind multiple text reading. In addition, the results highlight that accurate self-evaluation is achieved when high reading self-efficacy aligns with reading performance.