Investigations centered on electrical energy storage capacitors, particularly dielectric ceramic capacitors for high energy storage density, have garnered increasing interest in recent years. This study aims to substitute the widely used copper oxide (CuO) with cuprous oxide (Cu2O) in the synthesis of perovskite calcium copper titanate (CaCu3Ti4O12, CCTO) using the solid-state reaction method. We examined the effects of sintering temperature and duration on the structural stability, grain size, and dielectric performance of Cu2O-based CCTO ceramics. X-ray diffraction (XRD) analysis of the powder calcined at 1100°C and ceramics sintered at various temperatures and durations confirmed the successful synthesis of the CCTO phase. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses of the prepared pellets revealed that the Cu2O/CuO phase formed above 950°C, leading to enhanced densification at 1050°C (>96%). However, the Cu2O-based CCTO began to degrade around 1090°C. The dielectric constant and loss tangent values were optimal in the low-frequency range (<103 Hz), with values of 13,378 and 0.177, respectively. For the ceramics sintered at 1050°C with varying sintering durations (9–24 h), exhibited high permittivity and relatively low dielectric loss values in the frequency range of 20–106 Hz. Optimal values of 15,423 and 0.083 were achieved after sintering at 1050°C for 14 h. In contrast, longer sintering durations of 19 h and 24 h resulted in higher permittivity values of 19,943 and 21,392, respectively, and were associated with improved loss tangent values of approximately 0.114 and 0.127, respectively. These findings suggest that Cu2O is a suitable substitute for CuO in CCTO ceramics for applications at low frequencies. Future studies could explore the effects of Cu2O substitution on the electrical energy storage capacity of CCTO ceramics.