The determination of the stress intensity factor (SIF) is a critical aspect of fracture mechanics, providing valuable information about crack growth behavior and structural integrity. Caustic curve calculations are subject to errors and uncertainties. This research paper aims to provide a comprehensive review of error analysis in caustic curve calculations to reduce the errors in calculating SIF and hence the uncertainty estimation of the SIF calculation by caustic method. The determination of the stress intensity factor (SIF) is a critical aspect of fracture mechanics, providing valuable information about crack growth behavior and structural integrity. Caustic curve calculations are subject to errors and uncertainties. This research paper aims to provide a comprehensive review of error analysis in caustic curve calculations to reduce the errors in calculating SIF and hence the uncertainty estimation of the SIF calculation by caustic method. The uncertainty estimation was done for two methods for calculating SIF: the first method is measuring the diameter of the caustic curve, and the second is measuring the whole area. Regarding the sources of errors, it was found that the most effective source of error is the magnification ratio, followed by the thickness of the specimen; they have the highest sensitivity coefficients in the uncertainty budget. The calculated SIF by area reduced uncertainty from 1.73 to 0.945 Mpa mm-1/2, i.e., approximately 50%. It means that the method of calculating SIF by area is more accurate and precise than the method of measuring the whole diameter.