Use this Iron Intake Calculator to find how much iron a child, teen, or adult needs each day, based on age, sex, life stage, and diet type — plus how their current intake compares, and which foods can help close the gap.
Why Iron Matters at Every Age
Iron is essential for making hemoglobin, the protein in red blood cells that carries oxygen throughout the body. Iron needs shift throughout life: they rise during childhood growth spurts, climb sharply once menstruation begins, spike further during pregnancy to support increased blood volume and fetal development, and settle lower again after menopause. Iron is also directly involved in brain development, and iron deficiency in early childhood has been linked to lasting effects on cognitive and behavioral development.
Iron RDA by Age and Life Stage (Recommended Dietary Allowance)
| Age / Life Stage | RDA (mg/day) | Upper Limit (mg/day) |
|---|
| 1–3 years | 7 | 40 |
| 4–8 years | 10 | 40 |
| 9–13 years | 8 | 40 |
| 14–18 years, boys | 11 | 45 |
| 14–18 years, girls | 15 | 45 |
| 19–50 years, men | 8 | 45 |
| 19–50 years, women | 18 | 45 |
| 51+ years, all adults | 8 | 45 |
| Pregnant (any age) | 27 | 45 |
| Breastfeeding, 14–18 years | 10 | 45 |
| Breastfeeding, 19–50 years | 9 | 45 |
Vegetarians and vegans need more, at any age. Iron from plant sources (non-heme iron) is absorbed far less efficiently than iron from meat, poultry, and fish (heme iron). People on vegetarian or vegan diets are generally advised to aim for about 1.8 times the standard RDA to compensate for lower absorption — this applies equally to children, teens, and adults.
Heme vs. Non-Heme Iron, and What Affects Absorption
Heme iron comes from hemoglobin and myoglobin in meat, poultry, and fish. The body absorbs 15–35% of heme iron regardless of what else is eaten alongside it.
Non-heme iron comes from plants, eggs, dairy, and fortified foods. Absorption is much lower — often under 10% — and is strongly affected by other foods eaten at the same meal.
Vitamin C boosts non-heme absorption. Pairing plant iron sources with vitamin C-rich foods, like citrus fruit or bell peppers, can meaningfully increase how much is absorbed.
Calcium and tannins reduce it. Calcium (especially from supplements or a large glass of milk) and the tannins in tea and coffee can measurably reduce iron absorption when consumed at the same meal.
Who's Most at Risk of Low Iron?
Toddlers (1–3 years): Rapid growth combined with a diet that shifts away from iron-fortified infant formula or cereal puts toddlers at meaningfully higher risk of iron deficiency than older children.
Teen girls and women of reproductive age: Once menstruation begins, iron losses rise substantially and stay elevated until menopause. This is one of the highest-risk groups for iron deficiency at any age.
Pregnant women: Blood volume expands by up to 50% during pregnancy, and the growing fetus draws on maternal iron stores — pushing the RDA to 27 mg/day regardless of age.
Vegetarians and vegans: Lower iron bioavailability from plant-based diets raises the risk at every life stage if intake isn't deliberately increased.
Endurance athletes: Intense training can increase iron losses through sweat and gastrointestinal blood loss, and mildly low iron can affect performance and recovery before it shows up as full anemia.
Older adults: Reduced stomach acid production with age can lower non-heme iron absorption, and chronic conditions or medications common later in life can further increase risk.
Frequently Asked Questions
How do I know if I'm (or my child is) getting enough iron?
The only reliable way to know is a blood test ordered by a doctor — this calculator estimates dietary targets, not iron status. Signs like persistent fatigue, pale skin, or shortness of breath are worth bringing up at a checkup, at any age.
Can someone get too much iron from food alone?
It's uncommon from whole foods alone, but easy to exceed the upper limit with iron supplements or fortified products stacked on top of a normal diet — which is why supplements should only be taken under medical guidance.
Do vegetarian kids really need almost double the iron?
Yes — the commonly used 1.8× adjustment reflects how much less efficiently the body absorbs non-heme (plant-based) iron compared with heme iron from meat, not a difference in how much iron vegetarian diets contain.
Is iron deficiency the same as anemia?
No. Iron deficiency is low iron stores in the body; iron-deficiency anemia is a more advanced stage where hemoglobin production is already affected. A child can be iron deficient for a while before anemia shows up on a standard blood count.
References
1
Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc
Institute of Medicine (US) Panel on Micronutrients. National Academies Press, 2001
ncbi.nlm.nih.gov/books/NBK222310
2
Prediction of dietary iron absorption: an algorithm for calculating absorption and bioavailability of dietary iron
Hallberg L, Hulthén L. American Journal of Clinical Nutrition. 2000;71(5):1147–1160
pubmed.ncbi.nlm.nih.gov/10799377
3
Prevention, Screening, Diagnosis, and Treatment of Iron Deficiency and Iron Deficiency Anemia in Infants, Children, and Adolescents: Clinical Report
Powers JM, Heeney MM, Hord J, et al. American Academy of Pediatrics. Pediatrics. 2026;e2026077414
publications.aap.org/pediatrics
