If you drink 16 ounces of milk and eat two slices of cheese, your daily calcium requirements will be covered.
You can also get calcium from foods other than dairy products, but for most people, it can be difficult to get enough calcium from these sources. This is due to the fact that it requires a lot of knowledge about nutrients in food products in order to meet the requirements on a dairy-free diet.
Read more about the function of calcium in the human body in the report from Food and Agriculture Organization (FAO) “Human Vitamins and Minerals Requirements, chapter 11, Calcium”
For additional reading, download the full report “Human Vitamins and Minerals Requirements”