How much calcium a day? like if i am 16 and need 1300mg of calcium a day should i make sure that my body have absorbed 1300mg of calcium or just consume total intake of 1300mg calcium which in this case not all the 1300mg will be absorbed?

Recommended amounts are always what you should consume daily. We know you don't absorb all of what you consume. We take that into account when setting recommended daily intake. If you have a condition that affects your food absorption, such as gastric bypass surgery or a disease such as Crohns disease, then talk to your MD about what your intake should be.

Eating a healthy diet will provide all the calcium you need without calculating the milligrams. Eat whole foods like vegetables, beans and whole grains and you will get what your body needs. You do not have to have dairy products to obtain the calcium you need. The foods mentioned plus nuts and fruits are your best bet for obtaining everything you need besides Vitamin D3 and B12.