The United States Department of Agriculture (USDA) system has five retail cut yield (RCY) classes, whereas the former Canadian system had three total lean yield (TLY) classes. A total of 720 beef carcasses were used to develop a modified grade ruler, harmonizing the Canadian grades into five classes. Beef carcasses (n = 750) from three Canadian federally inspected facilities were graded using both USDA and Canadian (harmonized ruler) systems for external validation. Agreement between the USDA-RCY and the Canadian TLY was high (R² = 0.80). The validation between the harmonized ruler and the USDA-RCY showed a standard deviation of the difference of 1.32 and a coefficient of concordance of 0.83.