This study investigates the gamma-ray shielding performance of borate-based glasses containing varying mol% of CaO (calcium oxide). Using the melting and quenching technique, glass samples S1 (62B₂O₃-20Bi₂O₃-18CaO), S2 (58B₂O₃-20Bi₂O₃-22CaO), S3 (54B₂O₃-20Bi₂O₃-26CaO), and S4 (50B₂O₃-20Bi₂O₃-30CaO) were fabricated. The density of the glasses, calculated using the Archimedes technique, increased from 3.91 g/cm³ to 4.01 g/cm³ as the mol% of CaO increased. Phy-X online simulation software was used to compute the radiation shielding parameters, revealing that the linear attenuation coefficient (LAC) ranged from 1.036 cm⁻¹ to 1.030 cm⁻¹ at energies between 0.289 MeV and 2.253 MeV. Additionally, the half-value layer (HVL) at 0.347 MeV decreased from 0.596 cm in S1 (18% CaO) to 0.586 cm in S4 (30% CaO). The increase in the mol% of CaO in this study was accompanied by a significant reduction in the transmission factor (TF), leading to a maximum radiation protection efficiency (RPE) of 90.7% at lower energies with a thickness of 0.6 cm. This highlights the compatibility of CaO-doped borate-based glasses as a cost-effective and efficient material for gamma-ray shielding.