ABSTRACT Since the amount of food can affect the copper content, the copper content of different amounts of food (except foods without copper) is different. The copper content of some foods is inappropriately calculated per 100 kcal, 100 g or 100 mL, or the reference amount customarily consumed (RACC). Thus, making some food choices based on these calculations to achieve adequate copper intake may increase the risk of some chronic diseases. Calculating the copper content and determining appropriate copper levels (to achieve adequate copper intake) based on U.S. Food and Drug Administration (FDA), Codex Alimentarius Commission (CAC), and the proposed method were performed in 7,379 food items. Making some food choices based on the FDA and CAC per serving (the serving is derived from the RACC) or CAC per 100 g or 100 mL to achieve adequate copper intake exceeded energy needs, which could lead to overweight or obesity. Making some food choices based on the CAC per 100 kcal or CAC per 100 g or 100 mL to achieve adequate copper intake did not meet copper requirements, which could lead to copper deficiency. Some foods that met copper requirements were not appropriate food choices based on the CAC per 100 g or 100 mL or CAC per serving to achieve adequate copper intake. On the basis of the proposed method, calculating the copper content and determining appropriate copper levels in foods are performed by considering RACCs and the energy content of foods. Thus, making food choices based on the proposed method met copper requirements and did not exceed energy needs.