Calcium requirements for children range from 300-1200mg/day and need to be analyzed in relation to different ages. Broadly defined as children under the age of 18, in general, children aged 0-6 months need about 300mg of calcium per day, children aged 6-12 months need about 400mg of calcium per day, children aged 1-4 years need about 500mg per day, children aged 4-7 years need about 800mg per day; and children aged 7-17 years need about 1,000mg-1,200mg. So parents need to set up different calcium supplement programs according to the different ages of their children. Calcium deficiency may lead to abnormal bone development or even rickets. However, too much calcium can easily cause constipation and other gastrointestinal discomforts. Calcium supplementation should be carried out scientifically under the guidance of a doctor.