The amount of each vitamin and mineral your body needs isn't one fixed number — it depends on your age, your sex, and, for women, whether you're pregnant or breastfeeding. This calculator looks up the Recommended Dietary Allowance (RDA) or Adequate Intake (AI) for 12 key micronutrients from the NIH Office of Dietary Supplements, plus the Tolerable Upper Intake Level (UL) where one has been established, so you can see where your intake should land and how high is too high.

Where these numbers come from

The RDA and AI values in this calculator come from the National Institutes of Health Office of Dietary Supplements (NIH ODS) fact sheets, which in turn reflect the Dietary Reference Intakes (DRI) published by the National Academies of Sciences, Engineering, and Medicine (NASEM). An RDA is set when there's enough scientific evidence to calculate the average requirement plus a safety margin covering nearly all healthy people in a group. When the evidence isn't sufficient for a full RDA — currently the case for Vitamin K and potassium in this table — NASEM instead publishes an Adequate Intake (AI), based on observed intakes in healthy populations. Both are legitimate daily targets; the difference is in how rigorously the number was derived, not in how seriously you should take it.

Why age, sex, and life stage all matter

Age changes requirements because of shifts in absorption, bone metabolism, and body composition — calcium's RDA rises from 1,000 to 1,200 mg/day for women at 51 (when estrogen decline accelerates bone loss) and for men at 71. Sex differences mostly track body size and, for iron, menstrual blood loss — non-pregnant women 19-50 need more than twice the iron of men the same age.

Pregnancy and lactation cause the largest shifts of all: iron nearly doubles to support the expanding blood volume and fetal iron stores; folate rises to reduce neural tube defect risk; vitamin A and zinc increase to support fetal growth and, during lactation, milk production. This calculator's Life Stage tab lets you compare one nutrient across Adult, Pregnant, and Lactating side by side to see exactly how much the target moves.

Reading the Upper Limit correctly

The Upper Limit (UL) is not a target to aim for — it's a ceiling. It represents the highest average daily intake, from food, fortified products, and supplements combined, unlikely to cause adverse effects in almost all healthy people. Going over the UL occasionally (say, one high-dose day) is rarely dangerous on its own, but sustained intake above it — usually from supplements, since food alone rarely gets you there for most nutrients — raises the risk of side effects specific to that nutrient (for example, GI upset from very high vitamin C, or reduced zinc/copper absorption from excess supplemental zinc).

Three nutrients in this table — Vitamin K, Vitamin B12, and potassium — have no established UL, which the calculator reports as 'Not established.' That reflects insufficient evidence of toxicity at commonly consumed levels, not a guarantee that unlimited intake is risk-free, especially from supplements or in people with kidney or other conditions that affect nutrient clearance.

Limits of this calculator

This tool is a general reference lookup, not a personalized nutrition plan. It covers ages 19 and up only — pediatric RDAs are set differently and aren't included. It doesn't account for individual health conditions, medications, malabsorption, lab-confirmed deficiencies, athletic activity level, or specific dietary patterns (vegan, vegetarian, etc.), all of which can shift what's appropriate for a given person. If you have a diagnosed deficiency, a chronic condition affecting nutrient absorption, or take medications that interact with vitamins or minerals, talk to a clinician or registered dietitian before changing your diet or supplement routine — don't use this calculator to make that decision alone.