Dietary Reference Intake (RDA/RDI) Calculator
Look up Recommended Dietary Allowances (RDA) and Adequate Intakes (AI) for vitamins and minerals by age, sex, and life stage.
Based on USDA/NIH dietary reference intakes.
What Are Dietary Reference Intakes (DRIs)? Dietary Reference Intakes are a set of nutrient reference values developed by the Institute of Medicine (now National Academy of Medicine) in the United States and Canada. They replaced the earlier Recommended Dietary Allowances (RDAs) starting in 1997. DRIs are used to assess and plan the diets of healthy people.
Types of DRI Values RDA (Recommended Dietary Allowance): the daily intake sufficient to meet the needs of 97–98% of healthy people. AI (Adequate Intake): used when not enough data exist to establish an RDA. Set at a level assumed to ensure adequacy. EAR (Estimated Average Requirement): meets the needs of 50% of people. Used to assess population diets. UL (Tolerable Upper Intake Level): the maximum daily intake unlikely to cause adverse health effects. AMDR (Acceptable Macronutrient Distribution Range): range of intake for macronutrients associated with reduced disease risk.
Why Micronutrients Matter Vitamins and minerals are essential — the body cannot synthesize them in sufficient quantities. Deficiencies cause specific diseases: scurvy (vitamin C), rickets (vitamin D), beriberi (thiamin B1), pellagra (niacin B3), goiter (iodine), anemia (iron or B12). Even subclinical deficiencies impair immunity, cognition, and energy metabolism. Excess intake of fat-soluble vitamins (A, D, E, K) can accumulate and cause toxicity — unlike water-soluble vitamins which are excreted.
Key Vitamins and Minerals Vitamin D: bone health, immune function. Most people are deficient, especially at higher latitudes. Calcium: bone and teeth structure. Absorption requires vitamin D and is impaired by excess sodium or caffeine. Iron: oxygen transport in hemoglobin. Women of reproductive age need nearly double the amount of men. Folate (B9): essential for DNA synthesis. Critical in early pregnancy to prevent neural tube defects. Iodine: thyroid hormone production. Deficiency is the leading preventable cause of intellectual disability worldwide. Zinc: enzyme function, immune response, wound healing, taste and smell. Magnesium: over 300 enzymatic reactions; most adults are mildly deficient.
Life Stage Groups Requirements vary significantly by age and life stage. Infants have the highest needs per kg of body weight. Pregnancy increases needs for iron, folate, iodine, and calcium substantially. Older adults need more vitamin D and calcium to prevent osteoporosis and fractures. Athletes may need higher intakes of iron, zinc, and B vitamins.