Sky Strike 3DPlayIron and Water Intake
Published daily figures for iron and total water. Life stage changes the row. Body weight does not, on this page.
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Medical disclaimer. This page is general education for adults. It does not diagnose pregnancy, anemia, dehydration, or menopause, and it does not replace a clinician, midwife, or dietitian. Get in-person care for heavy bleeding, fainting, chest pain, a severe headache, or a baby who is hard to wake. Read the disclaimer before changing food, supplements, or feeding.
How to use: Enter an age from 14 up and choose pregnant, lactating, or neither. Check the vegetarian box only if you want the NIH 1.8 factor shown beside the RDA.
Iron figures on this page are the Recommended Dietary Allowances and Tolerable Upper Intake Levels printed by the NIH Office of Dietary Supplements, which restates the Food and Nutrition Board values. For girls and women who are not pregnant or lactating, the RDA is 15 mg a day at ages 14–18, 18 mg at ages 19–50, and 8 mg at age 51 and older. Pregnancy is 27 mg from ages 14 through 50. Lactation is 10 mg at ages 14–18 and 9 mg at ages 19–50. The upper limit from age 14 onward, including pregnancy and lactation in those tables, is 45 mg a day from food and supplements combined. A clinician sometimes prescribes more than that for deficiency. This page will not raise the limit on its own.
The NIH fact sheet also says people who follow vegetarian diets need 1.8 times as much iron, because non-heme iron from plants is absorbed less well than heme iron from meat, and because meat itself helps non-heme iron absorb. Check the box and the page multiplies the RDA by 1.8. That product can sit above 45 mg, especially in pregnancy, where 1.8 times 27 mg is 48.6 mg. The page flags that collision. The 1.8 factor is about planning meals. It is not an instruction to swallow supplements past the upper limit. Vitamin C with a plant meal is a food question; pill doses are a clinician question.
The NIH table does not list a pregnancy RDA at age 51 or older, so this page returns an explanation instead of copying the 27 mg row upward. Lactation rows also stop at age 50. If you are 51 or older and lactating, the page shows the 8 mg age line and says plainly that a separate lactation RDA is not published. Use that honesty in the conversation with a dietitian. Do not treat 8 mg as a custom lactation target this site invented.
Water figures are Adequate Intakes from the Institute of Medicine report Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate (National Academies Press, 2005). Total water includes drinking water, other drinks, and water in food. For women and girls the table is 2.3 liters a day at ages 14–18 (about 1.8 liters from beverages) and 2.7 liters from age 19 on (about 2.2 liters from beverages). Pregnancy, ages 14–50, is 3.0 liters total and about 2.3 liters from beverages. Lactation in that same age span is 3.8 liters total and about 3.1 liters from beverages. The report set those AIs from survey medians. For women 19 to 30, fluids were about 81 percent of the total and food the rest.
An Adequate Intake is not an RDA. The IOM wrote that healthy people can stay hydrated across a wide range of intakes, so a day under the AI is not automatically a problem, and the AI should not be read as a specific requirement. Hot weather and hard activity raise water needs. The report says that without giving a personal formula. A different tool already on this site, the water intake calculator, estimates from body weight, exercise minutes, and heat. Use it when you want that method. Use this page when you want the life-stage AI. The two answers differ because the methods differ. The lactation AI is published through age 50. Past that age, this page shows the 2.7 liter age line and says the lactation row has ended.
Neither number diagnoses anemia or dehydration. Pale skin, unusual fatigue, shortness of breath, a racing heart, or a craving for ice are reasons to test iron status, not reasons to guess a supplement dose. Dizziness, a dry mouth you cannot fix, and confusion are reasons for urgent care. Pair pregnancy numbers with the IOM weight ranges and the week counter. The calorie calculator already uses the Mifflin-St Jeor equation if the question is energy, and the body fat calculator already uses the U.S. Navy method. This page leaves both of those alone. Read the disclaimer before you buy a supplement from a result.
Frequently asked questions
How much iron does the NIH list for women 19 to 50?
18 mg a day. Pregnancy in that age span is 27 mg. Lactation is 9 mg. The upper limit is 45 mg a day.
What changes at age 51?
The iron RDA on the NIH table falls to 8 mg for women who are not pregnant. The water AI stays 2.7 liters of total water.
Why is the vegetarian number 1.8 times higher?
NIH states that factor because non-heme iron is absorbed less well. If the product exceeds 45 mg, do not chase it with supplements without a clinician.
Is 2.7 liters the amount I must drink?
No. That is the IOM total-water AI for women 19 and older, and about 2.2 liters of it is the beverage portion. The AI is not a daily requirement.
How is this different from the other water calculator?
The water intake calculator uses body weight and activity. This page uses the IOM life-stage table and also shows iron. Keep the page that matches the question.
Sources
- NIH Office of Dietary Supplements. Iron — Health Professional Fact Sheet. RDAs, the 45 mg upper limit from age 14, and the 1.8 vegetarian factor.
- Institute of Medicine. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. National Academies Press, 2005. Total-water AIs: 2.3 L (ages 14–18), 2.7 L (women 19+), 3.0 L in pregnancy, 3.8 L in lactation.
