Free Live Calculators

DRI Calculator — Daily Reference Intake by Age & Sex

Find your daily RDA/AI for protein, fiber, vitamin C, vitamin D, calcium, iron, and potassium by sex, age bracket, and pregnancy/lactation status.

Daily Reference Intakes — Female, 19–30 years
NutrientRecommended AmountType
Protein46gRDA
Fiber25gAI
Vitamin C75mgRDA
Vitamin D5mcg (200 IU)AI
Calcium1,000mgAI
Iron18mgRDA
Potassium2,600mgAI

Potassium figure note: This calculator uses the current 2019 National Academies AI of 3,400mg/day (male) and 2,600mg/day (female) — a significant reduction from the older 4,700mg/day figure still printed on many nutrition labels and older articles. Both numbers come from the same official body, just different revisions; the 3,400 / 2,600mg figures reflect the most current science.

RDA (Recommended Dietary Allowance) is the average daily intake sufficient to meet the nutrient needs of nearly all (97-98%) healthy people in a group — used when there's enough evidence to set a precise target. AI (Adequate Intake) is used instead when there isn't enough evidence for a formal RDA, and is based on observed intake levels in healthy populations. These are population-level guidelines, not individual prescriptions — actual needs vary by health status, body size, and activity level. This is not medical advice and does not replace personalized guidance from a doctor or registered dietitian, especially during pregnancy or lactation or if you have a medical condition affecting nutrient needs.
91% found this helpful

Reference Values

Last verified:
Category Range What It Means Status
Protein — Male, 19–70+ 56g/day (RDA) Flat RDA across adult male age brackets — protein needs don't change with age the way some micronutrients do. Good
Protein — Female, 19–70+ 46g/day (RDA) Flat RDA across adult female age brackets. Good
Protein — Pregnancy ★ 71g/day (RDA) Rises well above the non-pregnant 46g to support fetal growth and increased maternal blood volume. ★ Best
Protein — Lactation ★ 71g/day (RDA) Stays elevated at the same level as pregnancy to support milk production. ★ Best
Fiber — Male, 19–50 38g/day (AI) Adequate Intake, not a hard-cutoff RDA — most US adults fall well short of this figure. Good
Fiber — Male, 51+ 30g/day (AI) Drops slightly after 50 as average caloric intake tends to decline. Good
Fiber — Female, 19–50 25g/day (AI) Adequate Intake for adult women under 51. Good
Fiber — Female, 51+ 21g/day (AI) Drops slightly after 50, mirroring the male pattern. Good
Fiber — Pregnancy ★ 28g/day (AI) Higher than baseline female AI to help manage pregnancy-related constipation and support gut health. ★ Best
Fiber — Lactation ★ 29g/day (AI) Slightly above the pregnancy figure. ★ Best
Vitamin C — Male, 19+ 90mg/day (RDA) Flat RDA across adult male age brackets; smokers need an additional 35mg/day per NASEM guidance. Good
Vitamin C — Female, 19+ 75mg/day (RDA) Flat RDA across adult female age brackets. Good
Vitamin C — Pregnancy (19–50) ★ 85mg/day (RDA) Increases moderately above the non-pregnant female RDA. ★ Best
Vitamin C — Lactation (19–50) ★ 120mg/day (RDA) The highest Vitamin C RDA of any life stage, to replace what's transferred through breast milk. ★ Best
Vitamin D — Age 19–50 5mcg/day (200 IU) (AI) Same AI for both sexes at this age bracket. Good
Vitamin D — Age 51–70 10mcg/day (400 IU) (AI) Doubles from the 19–50 bracket as skin becomes less efficient at synthesizing Vitamin D from sunlight. Good
Vitamin D — Age 70+ ★ 15mcg/day (600 IU) (AI) Highest adult AI, reflecting further age-related decline in skin synthesis and dietary absorption. ★ Best
Vitamin D — Pregnancy/Lactation 5mcg/day (200 IU) (AI) Same as the standard 19–50 adult AI — pregnancy and lactation don't raise the Vitamin D AI. Good
Calcium — Age 19–50 1,000mg/day (AI) Same AI for both sexes at this age bracket. Good
Calcium — Age 51–70/70+ ★ 1,200mg/day (AI) Rises after 50 to help offset age-related bone density loss. ★ Best
Calcium — Pregnancy/Lactation, 19–50 1,000mg/day (AI) Simplified figure for the 19–50 adult bracket — the official NASEM tables split pregnant/lactating teens (14–18) at a higher 1,300mg/day, which doesn't apply to this calculator's 19+ scope. Good
Iron — Male, 19+ 8mg/day (RDA) Flat RDA across adult male age brackets. Good
Iron — Female, 19–50 ★ 18mg/day (RDA) More than double the male figure, to replace iron lost through menstruation. ★ Best
Iron — Female, 51+ 8mg/day (RDA) Drops to match the male RDA after menopause, once menstrual iron loss ends. Good
Iron — Pregnancy ★ 27mg/day (RDA) The highest iron RDA of any life stage, to support the large increase in maternal blood volume. ★ Best
Iron — Lactation 9–10mg/day (RDA) Drops back down after pregnancy since lactation typically suppresses menstruation. Good
Potassium — Male, 19+ 3,400mg/day (AI) Current 2019 NASEM figure — down from the older 4,700mg/day estimate still seen on many food labels. Good
Potassium — Female, 19+ 2,600mg/day (AI) Current 2019 NASEM figure — down from the older 4,700mg/day estimate. Good
Potassium — Pregnancy ★ 2,600–2,900mg/day (AI) Slightly above the non-pregnant female AI, varying by age sub-bracket within 19–50. ★ Best
Potassium — Lactation ★ 2,500–2,800mg/day (AI) Similar range to pregnancy, reflecting potassium needs for milk production. ★ Best
Potassium — Old pre-2019 figure (context only) 4,700mg/day The widely-cited older AI, replaced in 2019 but still printed on many nutrition labels and older articles — not the current authoritative figure. Okay

Source: National Academies of Sciences, Engineering, and Medicine (NASEM), 'Dietary Reference Intakes: Reference Tables' via NCBI Bookshelf (ods.od.nih.gov / ncbi.nlm.nih.gov/books/NBK545442); National Academies, 'Dietary Reference Intakes for Sodium and Potassium' (2019 revision); NIH Office of Dietary Supplements Nutrient Recommendations tool.

Worked Examples

Adult Male, Age 25

Sex
Male
Age Bracket
19–30
Status
Not applicable
Protein 56g · Fiber 38g · Vitamin C 90mg · Vitamin D 5mcg · Calcium 1,000mg · Iron 8mg · Potassium 3,400mg

Standard adult male DRI values — none of the age-based step-ups (Vitamin D, Calcium) or sex-based iron difference apply yet at 25.

Adult Female, Age 45

Sex
Female
Age Bracket
31–50
Status
Not applicable
Protein 46g · Fiber 25g · Vitamin C 75mg · Vitamin D 5mcg · Calcium 1,000mg · Iron 18mg · Potassium 2,600mg

Iron RDA (18mg) is more than double the male figure at this age because it still needs to replace iron lost through menstruation — that drops after menopause.

Postmenopausal Woman, Age 60

Sex
Female
Age Bracket
51–70
Status
Not applicable
Protein 46g · Fiber 21g · Vitamin C 75mg · Vitamin D 10mcg · Calcium 1,200mg · Iron 8mg · Potassium 2,600mg

Iron RDA drops from 18mg to 8mg — matching the male figure — because menstrual iron loss has ended. Calcium and Vitamin D both step up to support bone density.

Pregnant Woman, Age 28

Sex
Female
Age Bracket
19–30
Status
Pregnant
Protein 71g · Fiber 28g · Vitamin C 85mg · Vitamin D 5mcg · Calcium 1,000mg · Iron 27mg · Potassium 2,600–2,900mg

Protein and iron RDAs both jump substantially — iron to 27mg/day, the highest of any life stage — to support the large increase in maternal blood volume and fetal growth.

Breastfeeding Woman, Age 33

Sex
Female
Age Bracket
31–50
Status
Lactating
Protein 71g · Fiber 29g · Vitamin C 120mg · Vitamin D 5mcg · Calcium 1,000mg · Iron 9–10mg · Potassium 2,500–2,800mg

Vitamin C RDA (120mg) is the highest of any life stage to replace what's transferred through breast milk, while iron drops back down from the pregnancy figure since lactation typically suppresses menstruation.

How to Use This Calculator

  1. 1

    Select your sex

    Male or female — several nutrient values differ by sex, most notably iron and potassium.

  2. 2

    Choose your age bracket

    19–30, 31–50, 51–70, or 70+ — fiber, vitamin D, calcium, and iron all shift at certain age cutoffs.

  3. 3

    Set pregnancy/lactation status if applicable

    Appears only when Female is selected. Pregnancy and lactation raise several nutrient targets, sometimes substantially.

  4. 4

    Read your full nutrient table

    Shows the recommended daily amount and whether it's an RDA or AI for all seven nutrients at once, plus a note anywhere the figure needs context (like potassium's 2019 revision).

What Each Value Means

RDA (Recommended Dietary Allowance) (varies by nutrient)
The average daily intake level sufficient to meet the nutrient requirement of nearly all (97-98%) healthy individuals in a specific life-stage and sex group, set when there's enough evidence to calculate a precise requirement.
AI (Adequate Intake) (varies by nutrient)
A recommended daily intake level based on observed or experimentally determined intake by a group of healthy people, used when there isn't enough evidence to establish a formal RDA.
DRI (Dietary Reference Intake) (n/a)
The umbrella term for the full set of nutrient reference values — including RDA, AI, Estimated Average Requirement (EAR), and Tolerable Upper Intake Level (UL) — published by the National Academies of Sciences, Engineering, and Medicine.

Related Calculators

Frequently Asked Questions

What's the difference between RDA and AI?
Both are official Dietary Reference Intake (DRI) categories from the National Academies, but they're set with different levels of evidence. RDA (Recommended Dietary Allowance) is used when there's enough scientific data to calculate a precise average requirement, then adjusted upward to cover the needs of about 97-98% of healthy people in a group. AI (Adequate Intake) is used instead when the evidence isn't strong enough to set a formal RDA — it's based on observed average intake in healthy populations that show no signs of deficiency. Fiber, vitamin D, calcium, and potassium are all AI values on this calculator; protein, vitamin C, and iron are RDA values.
Why did the potassium recommendation change from 4,700mg to 3,400mg/2,600mg?
In 2019, the National Academies revised the potassium AI down from a single 4,700mg/day figure (used for both sexes) to separate, lower figures — 3,400mg/day for adult men and 2,600mg/day for adult women. The change reflected a reassessment of the evidence: the original 4,700mg figure was based on intake levels associated with lower blood pressure, but the 2019 review found the data didn't support that specific number as a requirement, and split the AI by sex for the first time. Many food labels and older articles still cite 4,700mg because label rules and older content haven't caught up to the 2019 revision — both numbers come from the same official source, just different years.
Does this calculator account for sodium, or just the seven nutrients listed?
This calculator covers protein, fiber, vitamin C, vitamin D, calcium, iron, and potassium — seven of the nutrients most commonly searched and most relevant for everyday diet planning. It doesn't include sodium (which has an official Chronic Disease Risk Reduction intake rather than an RDA/AI), or the dozens of other vitamins and minerals with DRI values, like B12, folate, magnesium, or zinc. Those may be added in a future update.
Why does my Iron RDA change so much between age brackets?
Iron is one of the few nutrients where the DRI changes sharply based on a physiological event rather than gradual aging. Women ages 19-50 need 18mg/day to replace iron lost through menstrual bleeding — more than double the 8mg/day that adult men need at any age. After menopause (reflected in the 51+ bracket on this calculator), that menstrual iron loss stops, and the female RDA drops to match the male 8mg/day figure. Pregnancy pushes the RDA even higher, to 27mg/day, to support the large increase in maternal blood volume.
Are these numbers safe to use during pregnancy without talking to a doctor?
Use them as a general reference point, not a substitute for prenatal care. The pregnancy and lactation figures on this calculator come directly from official National Academies DRI tables, but individual pregnancies can call for different targets — for example, some prenatal vitamins are formulated around slightly different iron or vitamin D amounts, and conditions like gestational diabetes or anemia can change what your doctor recommends. Always follow your OB-GYN or midwife's specific guidance over a general calculator, especially for iron and vitamin D, which have documented risks at both too-low and (for vitamin D) very high intakes.