The effects of calcium oxide (CaO) on the physical properties of the B₂O₃–Bi₂O₃–CaO glass system were investigated in this study. The glass samples studied have molar ratios ranging from 18 to 30 mol%. The density of the fabricated glass samples increases from 3.906 g/cm³ (62B18Ca) to 4.012 g/cm³ (50B30CaO). The molar volume decreased from 0.2040 cm³/mol (62B18Ca) to 0.1924 cm³/mol (50B30CaO). The increase in field strength (F) from 8.06 × 10⁻¹⁶ cm⁻² to 11.10 × 10⁻¹⁶ cm⁻², along with the reduction in the average distance between boron atoms (dB–B), indicates an enhancement in bond interaction strength. As a result, the rigidity of the glass increased. The glass sample 50B30Ca shows the highest improvement in physical properties and the lowest intermolecular distance, indicating that it is the most suitable material for applications such as radiation shielding and electronics.