Nutrient loss and accumulation as well as associated environmental degradation have been a concern for animal agriculture for many decades. Federal and New York (NY) regulations apply to Concentrated Animal Feeding Operations and a comprehensive nutrient management plan (CNMP) is required for regulated farms. The whole farm nutrient mass balance (NMB) calculator was created to evaluate the impact of CNMPs and field or herd farm management changes on the whole farms' nutrient use efficiency. This tool calculates the nitrogen (N), phosphorus (P) and potassium (K) imported onto and exported from the farm, and expresses the difference as N, P, and K balance per acre of cropland and per volume of milk produced. Farmers and their advisors can use the NMB calculator to compare their farm's nutrient balance to those of peers with similar milk production, to identify opportunities to increase nutrient use efficiency, and to monitor progress over time. The NMB calculator is used in a capstone course on whole farm nutrient management at Cornell University to communicate the challenges and opportunities in addressing the long-term sustainability of the dairy sector and to illustrate the potential for improvement over time. The objectives of this paper are to introduce the NMB calculator, outline the classroom NMB exercise, and describe both producer and agricultural student feedback on the usefulness of whole farm NMB assessment for reaching more sustainable balances. (Contains 4 tables and 2 figures.)