Daily Calcium Requirement Calculator

About this calculator

This calculator returns your Recommended Dietary Allowance (RDA) for calcium — the daily intake, in milligrams, expected to meet the needs of nearly all healthy people in a given age and sex group — based on reference values set by the National Institutes of Health Office of Dietary Supplements, derived from the Institute of Medicine's Dietary Reference Intakes.

The requirement shifts noticeably across the lifespan: teenagers aged 9-18 need a relatively high 1,300 mg/day during peak bone-building years, most adults aged 19-50 need 1,000 mg/day, and the requirement rises again to 1,200 mg/day for women 51+ and men 71+, reflecting the accelerated bone density loss that follows menopause and advanced age.

Dietitians, prenatal care providers, and anyone focused on bone health or osteoporosis prevention use this age-and-sex-specific RDA as the benchmark to check whether dietary calcium intake from foods like dairy, leafy greens, and fortified products, plus any supplements, is actually meeting daily needs.