BACKGROUND: In radiotherapy, the accuracy of dose calculation systems plays a key role in the treatment of cancer patients. OBJECTIVE: The current research aimed to evaluate the dose calculation accuracy of Monaco Treatment Planning System (TPS) in estimating the Effective Wedge Angle (EWA) using two different mathematical methods: Elekta formula and ICRU-24 formula. MATERIAL AND METHODS: In this experimental study, EWAs for different field sizes (5×5, 10×10, 15×15, 20×20, 25×25, and 30×30 cm RESULTS: The planned and measured EWAs are consistent with the Elekta formula, and the error value was less than ±0.5 in all radiation fields and EWAs. In the ICRU-24 formula, the maximum deviation was ±2.6° between the computational and practical EWAs. CONCLUSION: The Elekta-based analytical method demonstrates a good agreement between planned and measured EWAs, while the ICRU-24 formula exhibited the greatest discrepancies.