Introduction: This study analyses the predictive role of several specific components of early numerical skills on the fluency calculation. Method: A total of 122 students (Mean age = 69.89 months; SD = 3.44), 54 girls and 68 boys participated in the study. The early numeracy skills were assessed by the end of pre primary school education, and fluency calculation at the first year of primary school. Results: A multiple linear stepwise regression analysis showed a predictive model that explained 27.9% of the variance in fluency calculation. This model suggested that verbal counting (ß = 0.377), resulting counting (ß = 0.191) and estimation (ß = 0.159), were the most important numerical variables explained fluency calculation in first graders primary school. Discussion and Conclusions: Numerical skills predicted fluency calculation, however, was not predicted by relational math skills. The extensive importance of fluency calculation on learning mathematics is discussed.