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Iron intake calculator: how much per day

Short answer

The US Recommended Dietary Allowance for iron is 8 mg a day for adult men and 18 mg for women aged 19–50, dropping to 8 mg from 51. It is 27 mg in pregnancy and 9 mg while breastfeeding (19 and over). Vegetarians need 1.8 times as much, about 32.4 mg for a woman aged 19–50, because plant iron is absorbed less well.

Last reviewed 28 October 20263 published sourcesNot medical advice

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Iron intake calculator

US Dietary Reference Intakes for iron from age 1, by age, sex, pregnancy and breastfeeding.

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Iron: daily RDA by age and sex
Age	Female	Male	Upper limit
1–3 years	7 mg	7 mg	40 mg
4–8 years	10 mg	10 mg	40 mg
9–13 years	8 mg	8 mg	40 mg
14–18 years	15 mg	11 mg	45 mg
19–30 years	18 mg	8 mg	45 mg
31–50 years	18 mg	8 mg	45 mg
51–70 years	8 mg	8 mg	45 mg
71+ years	8 mg	8 mg	45 mg

Recommended Dietary Allowances and upper limits, mg a day, from the National Academies' DRI summary tables (NASEM, 2019 (DRI tables)).

Iron in pregnancy and breastfeeding
Age	Pregnancy	Breastfeeding	Upper limit
14–18 years	27 mg	10 mg	45 mg
19–30 years	27 mg	9 mg	45 mg
31–50 years	27 mg	9 mg	45 mg

Where the numbers come from

Iron RDAs come from the Institute of Medicine's 2001 report, which assumed a typical mixed diet. It concluded that the iron requirement is 1.8 times higher for vegetarians, because the iron in a vegetarian diet is less available to the body (IOM, 2001 (iron, zinc)).

The values in the tables are as printed in the National Academies' current DRI summary tables (NASEM, 2019 (DRI tables)). US food labels use a single Daily Value of 18 mg (FDA Daily Values), the amount for women aged 19–50.

Related tools

Zinc was set in the same 2001 report; see the zinc intake calculator. Eating plant-based? Check your protein too with the protein calculator.

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Common questions

How much iron does a woman need a day?

18 mg a day from 19 to 50, 8 mg from 51, 27 mg in pregnancy and 9 mg while breastfeeding (ages 19–50). Girls aged 14–18 need 15 mg.

Do vegetarians need more iron?

Yes. The Institute of Medicine estimated that the iron requirement is 1.8 times higher for vegetarians, because iron from a vegetarian diet is less available to the body. For a man that is about 14.4 mg a day instead of 8 mg.

What is the upper limit for iron?

45 mg a day from age 14, including pregnancy and breastfeeding, and 40 mg for younger children, counting food and supplements together. Don't take iron supplements beyond that unless a clinician has advised it.

Sources

Figures on this page were checked against these publications on 28 October 2026.

National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press; 2019. Appendix J: Dietary Reference Intakes Summary Tables. doi.org/10.17226/25353
Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: The National Academies Press; 2001. doi.org/10.17226/10026
U.S. Food and Drug Administration. Daily Value on the Nutrition and Supplement Facts labels. Content current as of 5 March 2024. www.fda.gov/food/nutrition-facts-label/daily-value-nutrition-and-supplement-facts-labels

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