Objectives: This pilot in vitro analytical observational study evaluated the accuracy of three apex locators—Root ZX mini (Morita), Endo Radar Plus (Woodpecker), and Endo Motor SCM-011 (Fanta)—in determining root canal length, comparing measurements obtained using manual and mechanized files against a reference value obtained through cone-beam computed tomography (CBCT). Materials and Methods: Sixty permanent human teeth were randomly distributed into three groups according to the apex locator used. Root canal length was measured with manual files (without motor) and with mechanized files driven by endodontic motors with integrated apex locator functionality. Absolute errors were calculated in relation to the reference value, and statistical analyses were performed using Student's t-test and ANOVA (p<0.05). Results: Manual files showed a lower mean absolute error (0.253 mm) than m...